[devel] Imported from libpng-1.5.4beta01.tar

outside of an unknown-chunk block in png.h because they are also
needed for other uses.

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.5.3beta03 - April 17, 2011
+Libpng 1.5.4beta01 - June 14, 2011
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -9,20 +9,20 @@ Files available for download:
 Source files with LF line endings (for Unix/Linux) and with a
 "configure" script
 
-   1.5.3beta03.tar.xz (LZMA-compressed, recommended)
-   1.5.3beta03.tar.gz
-   1.5.3beta03.tar.bz2
+   1.5.4beta01.tar.xz (LZMA-compressed, recommended)
+   1.5.4beta01.tar.gz
+   1.5.4beta01.tar.bz2
 
 Source files with CRLF line endings (for Windows), without the
 "configure" script
 
-   lp153b03.7z  (LZMA-compressed, recommended)
-   lp153b03.zip
+   lp154b01.7z  (LZMA-compressed, recommended)
+   lp154b01.zip
 
 Other information:
 
-   1.5.3beta03-README.txt
-   1.5.3beta03-LICENSE.txt
+   1.5.4beta01-README.txt
+   1.5.4beta01-LICENSE.txt
 
 Changes since the last public release (1.5.2):
 
@@ -38,7 +38,7 @@ Version 1.5.3beta02 [April 3, 2011]
   Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
   Optimize the zlib CMF byte in non-IDAT compressed chunks
 
-Version 1.5.3beta03 [April 17, 2011]
+Version 1.5.3beta03 [April 16, 2011]
   Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
     snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
     than __STDC__ (John Bowler).
@@ -52,7 +52,146 @@ Version 1.5.3beta03 [April 17, 2011]
   Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
     pngwutil.c (John Bowler).
   Fixed bug with stripping the filler or alpha channel when writing, that
-    was introduced in libpng-1.5.2beta01.
+    was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+  Updated pngtest.png with the new zlib CMF optimization.
+  Cleaned up conditional compilation code and of background/gamma handling
+    Internal changes only except a new option to avoid compiling the
+    png_build_grayscale_palette API (which is not used at all internally.)
+    The main change is to move the transform tests (READ_TRANSFORMS,
+    WRITE_TRANSFORMS) up one level to the caller of the APIs.  This avoids
+    calls to spurious functions if all transforms are disabled and slightly
+    simplifies those functions.  Pngvalid modified to handle this.
+    A minor change is to stop the strip_16 and expand_16 interfaces from
+    disabling each other; this allows the future alpha premultiplication
+    code to use 16-bit intermediate values while still producing 8-bit output.
+    png_do_background and png_do_gamma have been simplified to take a single
+    pointer to the png_struct rather than pointers to every item required
+    from the png_struct. This makes no practical difference to the internal
+    code.
+  A serious bug in the pngvalid internal routine 'standard_display_init' has
+    been fixed - this failed to initialize the red channel and accidentally
+    initialized the alpha channel twice.
+  Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+    avoid a clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+  Added appropriate feature test macros to ensure libpng sees the correct API
+   _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and pngvalid.c to ensure
+    that POSIX conformant systems disable non-POSIX APIs.  _ISOC99_SOURCE is
+    defined in pngpriv.h to obtain the ISO C99 snprintf definition, when
+    available.
+  Removed png_snprintf and added formatted warning messages.  This change adds
+    internal APIs to allow png_warning messages to have parameters without
+    requiring the host OS to implement snprintf.  As a side effect the
+    dependency of the tIME-supporting RFC1132 code on stdio is removed and
+    PNG_NO_WARNINGS does actually work now.
+  Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+    optimization configureable.
+  IDAT compression failed if preceded by a compressed text chunk (bug
+    introduced in libpng-1.5.3beta01-02).  This was because the attempt to
+    reset the zlib stream in png_write_IDAT happened after the first IDAT
+    chunk had been deflated - much too late.  In this change internal
+    functions were added to claim/release the z_stream and, hopefully, make
+    the code more robust.  Also deflateEnd checking is added - previously
+    libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+  Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+  Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+  Added expand_16 support to the high level interface.
+  Added named value and 'flag' gamma support to png_set_gamma.  Made a minor
+    change from the previous (unreleased) ABI/API to hide the exact value used
+    for Macs - it's not a good idea to embed this in the ABI!
+  Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+    from pngpriv.h to png.h because they must be visible to applications
+    that call png_set_unknown_chunks().
+  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+    before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+  Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+  Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+  The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+    parameters are supplied by the caller), while in the absence of cHRM
+    sRGB/Rec 709 values are still used.
+  The bKGD chunk no longer overwrites the background value set by
+    png_set_background(), allowing the latter to be used before the file
+    header is read. It never performed any useful function to override
+    the default anyway.
+  Added memory overwrite and palette image checks to pngvalid.c
+    Previously palette image code was poorly checked. Since the transformation
+    code has a special palette path in most cases this was a severe weakness.
+  Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+    expanding an indexed image, always expand to RGBA if transparency is
+    present.
+
+Version 1.5.3beta09 [May 17, 2011]
+ Reversed earlier 1.5.3 change of transformation order; move png_expand_16 back.
+   The change doesn't work because it requires 16-bit gamma tables when the code
+   only generates 8-bit ones.  This fails silently; the libpng code just doesn't
+   do any gamma correction.  Moving the tests back leaves the old, inaccurate,
+   8-bit gamma calculations, but these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+  png_set_background() and png_expand_16() did not work together correctly.
+    This problem is present in 1.5.2; if png_set_background is called with
+    need_expand false and the matching 16 bit color libpng erroneously just
+    treats it as an 8-bit color because of where png_do_expand_16 is in the
+    transform list.  This simple fix reduces the supplied colour to 8-bits,
+    so it gets smashed, but this is better than the current behavior.
+  Added tests for expand16, more fixes for palette image tests to pngvalid.
+    Corrects the code for palette image tests and disables attempts to
+    validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+  No changes.
+
+Version 1.5.3rc02 [June 8, 2011]
+  Fixed uninitialized memory read in png_format_buffer() (Bug report by
+    Frank Busse, related to CVE-2004-0421).
+
+Version 1.5.3beta11 [June 11, 2011]
+  Fixed png_handle_sCAL which is broken in 1.5; added sCAL to pngtest.png
+  Revised documentation about png_set_user_limits() to say that it also affects
+    png writing.
+  Revised handling of png_set_user_limits() so that it can increase the
+    limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
+    reduce it.
+  Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
+    wrong (high by one) 25% of the time. Dividing by 257 with rounding is
+    wrong in 128 out of 65536 cases. Getting the right answer all the time
+    without division is easy.
+  Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
+  Added projects/owatcom, an IDE project for OpenWatcom to replace
+    scripts/makefile.watcom.  This project works with OpenWatcom 1.9. The
+    IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
+    The project is configurable, unlike the Visual Studio project, so long
+    as the developer has an awk.
+  Changed png_set_gAMA to limit the gamma value range so that the inverse
+    of the stored value cannot overflow the fixed point representation,
+    and changed other things OpenWatcom warns about.
+  Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
+    pngvalid to build when ALPHA_MODE is not supported, which is required if
+    it is to build on libpng 1.4.
+  Removed string/memory macros that are no longer used and are not
+    necessarily fully supportable, particularly png_strncpy and png_snprintf.
+  Added log option to pngvalid.c and attempted to improve gamma messages.
+
+Version 1.5.3 [omitted]
+  People found the presence of a beta release following an rc release
+    to be confusing; therefore we bump the version to libpng-1.5.4beta01
+    and there will be no libpng-1.5.3 release.
+
+Version 1.5.4beta01 [June 14, 2011]
+  Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+    to get the same (inaccurate) output as libpng-1.5.2 and earlier.
+  Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
+    outside of an unknown-chunk block in png.h because they are also
+    needed for other uses.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
 (subscription required; visit

CHANGES

@@ -15,7 +15,7 @@ Version 0.3
   fixed some bugs in writer
   interfaced with zlib 0.5
   added K&R support
-  added check for 64 KB blocks for 16 bit machines
+  added check for 64 KB blocks for 16-bit machines
 
 Version 0.4
   cleaned up code and commented code
@@ -74,7 +74,7 @@ Version 0.82 [September, 1995]
 Version 0.85 [December, 1995]
   added more medium model code (almost everything's a far)
   added i/o, error, and memory callback functions
-  fixed some bugs (16 bit, 4 bit interlaced, etc.)
+  fixed some bugs (16-bit, 4-bit interlaced, etc.)
   added first run progressive reader (barely tested)
 
 Version 0.86 [January, 1996]
@@ -2935,7 +2935,7 @@ Version 1.5.0beta36 [July 29, 2010]
     PNG_INTERLACE transform and to get the number of rows in the current
     pass.
   A new test program, pngvalid.c, validates the gamma code.
-  Errors in the 16 bit gamma correction (overflows) have been corrected.
+  Errors in the 16-bit gamma correction (overflows) have been corrected.
   cHRM chunk testing is done consistently (previously the floating point
     API bypassed it, because the test really didn't work on FP, now the test
     is performed on the actual values to be stored in the PNG file so it
@@ -3227,7 +3227,7 @@ Version 1.5.1beta10 [January 27, 2010]
 Version 1.5.1beta11 [January 28, 2011]
   Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
   Corrected local variable type in new API png_process_data_skip()
-    The type was self-evidently incorrect but only causes problems on 64 bit
+    The type was self-evidently incorrect but only causes problems on 64-bit
     architectures.
   Added transform tests to pngvalid and simplified the arguments.
 
@@ -3299,7 +3299,7 @@ Version 1.5.3beta02 [April 3, 2011]
   Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
   Optimize the zlib CMF byte in non-IDAT compressed chunks
 
-Version 1.5.3beta03 [April 17, 2011]
+Version 1.5.3beta03 [April 16, 2011]
   Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
     snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
     than __STDC__ (John Bowler).
@@ -3313,7 +3313,148 @@ Version 1.5.3beta03 [April 17, 2011]
   Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
     pngwutil.c (John Bowler).
   Fixed bug with stripping the filler or alpha channel when writing, that
-    was introduced in libpng-1.5.2beta01.
+    was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+  Updated pngtest.png with the new zlib CMF optimization.
+  Cleaned up conditional compilation code and of background/gamma handling
+    Internal changes only except a new option to avoid compiling the
+    png_build_grayscale_palette API (which is not used at all internally.)
+    The main change is to move the transform tests (READ_TRANSFORMS,
+    WRITE_TRANSFORMS) up one level to the caller of the APIs.  This avoids
+    calls to spurious functions if all transforms are disabled and slightly
+    simplifies those functions.  Pngvalid modified to handle this.
+    A minor change is to stop the strip_16 and expand_16 interfaces from
+    disabling each other; this allows the future alpha premultiplication
+    code to use 16-bit intermediate values while still producing 8-bit output.
+    png_do_background and png_do_gamma have been simplified to take a single
+    pointer to the png_struct rather than pointers to every item required
+    from the png_struct. This makes no practical difference to the internal
+    code.
+  A serious bug in the pngvalid internal routine 'standard_display_init' has
+    been fixed - this failed to initialize the red channel and accidentally
+    initialized the alpha channel twice.
+  Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+    avoid a possible clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+  Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
+    correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
+    pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
+  Removed png_snprintf and added formatted warning messages.  This change adds
+    internal APIs to allow png_warning messages to have parameters without
+    requiring the host OS to implement snprintf.  As a side effect the
+    dependency of the tIME-supporting RFC1132 code on stdio is removed and
+    PNG_NO_WARNINGS does actually work now.
+  Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
+    was introduced in libpng-1.2.20beta01.
+  Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+    optimization configureable.
+  IDAT compression failed if preceded by a compressed text chunk (bug
+    introduced in libpng-1.5.3beta01-02).  This was because the attempt to
+    reset the zlib stream in png_write_IDAT happened after the first IDAT
+    chunk had been deflated - much too late.  In this change internal
+    functions were added to claim/release the z_stream and, hopefully, make
+    the code more robust.  Also deflateEnd checking is added - previously
+    libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+  Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+  Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+  Added expand_16 support to the high level interface.
+  Added named value and 'flag' gamma support to png_set_gamma.  Made a minor
+    change from the previous (unreleased) ABI/API to hide the exact value used
+    for Macs - it's not a good idea to embed this in the ABI!
+  Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+    from pngpriv.h to png.h because they must be visible to applications
+    that call png_set_unknown_chunks().
+  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+    before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+  Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+  Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+  The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+    parameters are supplied by the caller), while in the absence of cHRM
+    sRGB/Rec 709 values are still used.
+  The bKGD chunk no longer overwrites the background value set by
+    png_set_background(), allowing the latter to be used before the file
+    header is read. It never performed any useful function to override
+    the default anyway.
+  Added memory overwrite and palette image checks to pngvalid.c
+    Previously palette image code was poorly checked. Since the transformation
+    code has a special palette path in most cases this was a severe weakness.
+  Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+    expanding an indexed image, always expand to RGBA if transparency is
+    present.
+
+Version 1.5.3beta09 [May 17, 2011]
+  Reversed earlier 1.5.3 change of transformation order; move png_expand_16
+    back where it was.  The change doesn't work because it requires 16-bit
+    gamma tables when the code only generates 8-bit ones.  This fails
+    silently; the libpng code just doesn't do any gamma correction.  Moving
+    the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
+    these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+
+  png_set_background() and png_expand_16() did not work together correctly.
+    This problem is present in 1.5.2; if png_set_background is called with
+    need_expand false and the matching 16 bit color libpng erroneously just
+    treats it as an 8-bit color because of where png_do_expand_16 is in the
+    transform list.  This simple fix reduces the supplied colour to 8-bits,
+    so it gets smashed, but this is better than the current behavior.
+  Added tests for expand16, more fixes for palette image tests to pngvalid.
+    Corrects the code for palette image tests and disables attempts to
+    validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+  No changes.
+
+Version 1.5.3rc02 [June 8, 2011]
+  Fixed uninitialized memory read in png_format_buffer() (Bug report by
+    Frank Busse, related to CVE-2004-0421).
+
+Version 1.5.3beta11 [June 11, 2011]
+  Fixed png_handle_sCAL which is broken in 1.5; added sCAL to pngtest.png
+  Revised documentation about png_set_user_limits() to say that it also affects
+    png writing.
+  Revised handling of png_set_user_limits() so that it can increase the
+    limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
+    reduce it.
+  Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
+    wrong (high by one) 25% of the time. Dividing by 257 with rounding is
+    wrong in 128 out of 65536 cases. Getting the right answer all the time
+    without division is easy.
+  Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
+  Added projects/owatcom, an IDE project for OpenWatcom to replace
+    scripts/makefile.watcom.  This project works with OpenWatcom 1.9. The
+    IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
+    The project is configurable, unlike the Visual Studio project, so long
+    as the developer has an awk.
+  Changed png_set_gAMA to limit the gamma value range so that the inverse
+    of the stored value cannot overflow the fixed point representation,
+    and changed other things OpenWatcom warns about.
+  Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
+    pngvalid to build when ALPHA_MODE is not supported, which is required if
+    it is to build on libpng 1.4.
+  Removed string/memory macros that are no longer used and are not
+    necessarily fully supportable, particularly png_strncpy and png_snprintf.
+  Added log option to pngvalid.c and attempted to improve gamma messages.
+  
+Version 1.5.3 [omitted]
+  People found the presence of a beta release following an rc release
+    to be confusing; therefore we bump the version to libpng-1.5.4beta01
+    and there will be no libpng-1.5.3 release.
+
+Version 1.5.4beta01 [June 14, 2011]
+  Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+    to get the same (inaccurate) output as libpng-1.5.2 and earlier.
+  Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
+    outside of an unknown-chunk block in png.h because they are also
+    needed for other uses.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CMakeLists.txt

@@ -33,7 +33,7 @@ enable_testing()
 
 set(PNGLIB_MAJOR 1)
 set(PNGLIB_MINOR 5)
-set(PNGLIB_RELEASE 3)
+set(PNGLIB_RELEASE 4)
 set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
 set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})
 
@@ -147,10 +147,6 @@ set(pngtest_sources
 
 add_definitions(-DPNG_CONFIGURE_LIBPNG)
 
-if(_AIX)
-  add_definitions(-D_ALL_SOURCE)
-endif(_AIX)
-
 if(MSVC)
   add_definitions(-DPNG_NO_MODULEDEF -D_CRT_SECURE_NO_DEPRECATE)
 endif(MSVC)
@@ -264,7 +260,7 @@ install(CODE ${PNG_CONFIG_INSTALL_CODE})
 # SET UP LINKS
 if(PNG_SHARED)
   set_target_properties(${PNG_LIB_NAME} PROPERTIES
-#   VERSION 15.${PNGLIB_RELEASE}.1.5.3beta03
+#   VERSION 15.${PNGLIB_RELEASE}.1.5.4beta01
     VERSION 15.${PNGLIB_RELEASE}.0
     SOVERSION 15
     CLEAN_DIRECT_OUTPUT 1)

LICENSE

@@ -10,7 +10,7 @@ this sentence.
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.5.3beta03, April 17, 2011, are
+libpng versions 1.2.6, August 15, 2004, through 1.5.4beta01, June 14, 2011, are
 Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -108,4 +108,4 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 17, 2011
+June 14, 2011

Makefile.am

@@ -18,13 +18,13 @@ pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 pngvalid_SOURCES = pngvalid.c
 pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 TESTS = test-pngtest.sh test-pngvalid-simple.sh test-pngvalid-full.sh
-TESTS_ENVIRONMENT= srcdir=$(srcdir) 
+TESTS_ENVIRONMENT= srcdir=$(srcdir)
 
 # man pages
 dist_man_MANS= libpng.3 libpngpf.3 png.5
 
 # generate the -config scripts if required
-binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config 
+binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
 EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
 bin_SCRIPTS= @binconfigs@
 
@@ -159,10 +159,10 @@ scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.ou
 # be empty - no non-standard defines
 scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk
 	rm -f $@ dfn?.out
-	test -z "$(CPPFLAGS)" 
+	test -z "$(CPPFLAGS)"
 	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
 	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out\
-	    logunsupported=3 - ${srcdir}/scripts/pnglibconf.dfa 1>&2
+	    logunsupported=4 - ${srcdir}/scripts/pnglibconf.dfa 1>&2
 	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
 	rm dfn1.out
 	mv dfn2.out $@

Makefile.in

@@ -252,7 +252,7 @@ am__tar = @am__tar@
 am__untar = @am__untar@
 
 # generate the -config scripts if required
-binconfigs = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config 
+binconfigs = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
 bindir = @bindir@
 build = @build@
 build_alias = @build_alias@
@@ -310,7 +310,7 @@ pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 pngvalid_SOURCES = pngvalid.c
 pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 TESTS = test-pngtest.sh test-pngvalid-simple.sh test-pngvalid-full.sh
-TESTS_ENVIRONMENT = srcdir=$(srcdir) 
+TESTS_ENVIRONMENT = srcdir=$(srcdir)
 
 # man pages
 dist_man_MANS = libpng.3 libpngpf.3 png.5
@@ -413,7 +413,7 @@ config.h: stamp-h1
 stamp-h1: $(srcdir)/config.h.in $(top_builddir)/config.status
 	@rm -f stamp-h1
 	cd $(top_builddir) && $(SHELL) ./config.status config.h
-$(srcdir)/config.h.in: @MAINTAINER_MODE_TRUE@ $(am__configure_deps) 
+$(srcdir)/config.h.in: @MAINTAINER_MODE_TRUE@ $(am__configure_deps)
 	($(am__cd) $(top_srcdir) && $(AUTOHEADER))
 	rm -f stamp-h1
 	touch $@
@@ -455,7 +455,7 @@ clean-libLTLIBRARIES:
 	  echo "rm -f \"$${dir}/so_locations\""; \
 	  rm -f "$${dir}/so_locations"; \
 	done
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES) 
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la: $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES)
 	$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LINK) -rpath $(libdir) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS) $(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LIBADD) $(LIBS)
 
 clean-checkPROGRAMS:
@@ -466,10 +466,10 @@ clean-checkPROGRAMS:
 	list=`for p in $$list; do echo "$$p"; done | sed 's/$(EXEEXT)$$//'`; \
 	echo " rm -f" $$list; \
 	rm -f $$list
-pngtest$(EXEEXT): $(pngtest_OBJECTS) $(pngtest_DEPENDENCIES) 
+pngtest$(EXEEXT): $(pngtest_OBJECTS) $(pngtest_DEPENDENCIES)
 	@rm -f pngtest$(EXEEXT)
 	$(LINK) $(pngtest_OBJECTS) $(pngtest_LDADD) $(LIBS)
-pngvalid$(EXEEXT): $(pngvalid_OBJECTS) $(pngvalid_DEPENDENCIES) 
+pngvalid$(EXEEXT): $(pngvalid_OBJECTS) $(pngvalid_DEPENDENCIES)
 	@rm -f pngvalid$(EXEEXT)
 	$(LINK) $(pngvalid_OBJECTS) $(pngvalid_LDADD) $(LIBS)
 install-binSCRIPTS: $(bin_SCRIPTS)
@@ -1319,7 +1319,7 @@ scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.ou
 # be empty - no non-standard defines
 scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk
 	rm -f $@ dfn?.out
-	test -z "$(CPPFLAGS)" 
+	test -z "$(CPPFLAGS)"
 	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
 	$(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out\
 	    logunsupported=1 - ${srcdir}/scripts/pnglibconf.dfa 1>&2

README

@@ -1,4 +1,4 @@
-README for libpng version 1.5.3beta03 - April 17, 2011 (shared library 15.0)
+README for libpng version 1.5.4beta01 - June 14, 2011 (shared library 15.0)
 See the note about version numbers near the top of png.h
 
 See INSTALL for instructions on how to install libpng.
@@ -114,19 +114,16 @@ given in previous versions of this document.  He and Andreas will
 read mail addressed to the png-implement list, however.
 
 Please do not send general questions about PNG.  Send them to
-the (png-list at ccrc.wustl.edu, subscription required, write to
-majordomo at ccrc.wustl.edu with "subscribe png-list" in your message).
-On the other hand,
-please do not send libpng questions to that address, send them to me
-or to the png-implement list.  I'll
-get them in the end anyway.  If you have a question about something
+png-mng-misc at lists.sf.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
+subscribe).  If you have a question about something
 in the PNG specification that is related to using libpng, send it
 to me.  Send me any questions that start with "I was using libpng,
 and ...".  If in doubt, send questions to me.  I'll bounce them
 to others, if necessary.
 
 Please do not send suggestions on how to change PNG.  We have
-been discussing PNG for nine years now, and it is official and
+been discussing PNG for sixteen years now, and it is official and
 finished.  If you have suggestions for libpng, however, I'll
 gladly listen.  Even if your suggestion is not used immediately,
 it may be used later.

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.68 for libpng 1.5.3beta03.
+# Generated by GNU Autoconf 2.68 for libpng 1.5.4beta01.
 #
 # Report bugs to <png-mng-implement@lists.sourceforge.net>.
 #
@@ -570,8 +570,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='libpng'
 PACKAGE_TARNAME='libpng'
-PACKAGE_VERSION='1.5.3beta03'
-PACKAGE_STRING='libpng 1.5.3beta03'
+PACKAGE_VERSION='1.5.4beta01'
+PACKAGE_STRING='libpng 1.5.4beta01'
 PACKAGE_BUGREPORT='png-mng-implement@lists.sourceforge.net'
 PACKAGE_URL=''
 
@@ -1307,7 +1307,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures libpng 1.5.3beta03 to adapt to many kinds of systems.
+\`configure' configures libpng 1.5.4beta01 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1377,7 +1377,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of libpng 1.5.3beta03:";;
+     short | recursive ) echo "Configuration of libpng 1.5.4beta01:";;
    esac
   cat <<\_ACEOF
 
@@ -1485,7 +1485,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-libpng configure 1.5.3beta03
+libpng configure 1.5.4beta01
 generated by GNU Autoconf 2.68
 
 Copyright (C) 2010 Free Software Foundation, Inc.
@@ -1908,7 +1908,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by libpng $as_me 1.5.3beta03, which was
+It was created by libpng $as_me 1.5.4beta01, which was
 generated by GNU Autoconf 2.68.  Invocation command line was
 
   $ $0 $@
@@ -2723,7 +2723,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='libpng'
- VERSION='1.5.3beta03'
+ VERSION='1.5.4beta01'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -2787,10 +2787,10 @@ fi
 
 
 
-PNGLIB_VERSION=1.5.3beta03
+PNGLIB_VERSION=1.5.4beta01
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=5
-PNGLIB_RELEASE=3
+PNGLIB_RELEASE=4
 
 
 
@@ -13040,7 +13040,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by libpng $as_me 1.5.3beta03, which was
+This file was extended by libpng $as_me 1.5.4beta01, which was
 generated by GNU Autoconf 2.68.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -13106,7 +13106,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-libpng config.status 1.5.3beta03
+libpng config.status 1.5.4beta01
 configured by $0, generated by GNU Autoconf 2.68,
   with options \\"\$ac_cs_config\\"
 

configure.ac

@@ -18,15 +18,15 @@ AC_PREREQ(2.59)
 
 dnl Version number stuff here:
 
-AC_INIT([libpng], [1.5.3beta03], [png-mng-implement@lists.sourceforge.net])
+AC_INIT([libpng], [1.5.4beta01], [png-mng-implement@lists.sourceforge.net])
 AM_INIT_AUTOMAKE
 dnl stop configure from automagically running automake
 AM_MAINTAINER_MODE
 
-PNGLIB_VERSION=1.5.3beta03
+PNGLIB_VERSION=1.5.4beta01
 PNGLIB_MAJOR=1
 PNGLIB_MINOR=5
-PNGLIB_RELEASE=3
+PNGLIB_RELEASE=4
 
 dnl End of version number stuff
 

contrib/gregbook/Makefile.w32

@@ -18,7 +18,7 @@
 # "c:\windows\command.com /e:4096" as the program command line and set the
 # working directory to this directory.  Then double-click to open the new
 # DOS-prompt window with a bigger environment and retry the commands above.
-# 
+#
 # This makefile assumes libpng and zlib have already been built or downloaded
 # and are in subdirectories at the same level as the current subdirectory
 # (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.

contrib/gregbook/README

@@ -104,7 +104,7 @@ BUILD INSTRUCTIONS
      unpacked the source code.
 
      For MSVC, set up the necessary environment variables by invoking
- 
+
         %devstudio%\vc\bin\vcvars32.bat
 
      where where %devstudio% is the installation directory for MSVC /

contrib/gregbook/makevms.com

@@ -20,13 +20,13 @@ $ if zpath .eqs. ""
 $ then
 $   write sys$output "zlib include not found. Exiting..."
 $   exit 2
-$ endif 
+$ endif
 $!
 $ if pngpath .eqs. ""
 $ then
 $   write sys$output "libpng include not found. Exiting..."
 $   exit 2
-$ endif 
+$ endif
 $!
 $!    Look for the compiler used.
 $!

contrib/gregbook/rpng-x.c

@@ -252,8 +252,8 @@ int main(int argc, char **argv)
             else {
                 bgstr = *argv;
                 if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error; 
-                else 
+                    ++error;
+                else
                     have_bg = TRUE;
             }
         } else {

contrib/pngminim/decoder/README

@@ -7,4 +7,4 @@ Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
 on the make command line.
 
 If you prefer to use the shared libraries, go to contrib/pngminus
-and build the png2pnm application there. 
+and build the png2pnm application there.

contrib/pngminim/encoder/README

@@ -7,4 +7,4 @@ Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
 on the make command line.
 
 If you prefer to use the shared libraries, go to contrib/pngminus
-and build the pnm2png application there. 
+and build the pnm2png application there.

contrib/pngminim/preader/README

@@ -8,8 +8,8 @@ on the make command line.
 
 Edit makefile if required, to find your X library and include files,
 then
-    
+
     make ZLIBSRC=directory
- 
+
 If you prefer to use the shared libraries, go to contrib/gregbook
-and build the rpng2-x application there. 
+and build the rpng2-x application there.

contrib/pngminus/png2pnm.c

@@ -403,7 +403,7 @@ BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL a
             if (bit_depth == 16){
               dep_16 = (long) *pix_ptr++;
               fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
-            }  
+            }
             else
               fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
         }

contrib/pngsuite/README

@@ -6,9 +6,9 @@ pngsuite
 Permission to use, copy, modify, and distribute these images for any
 purpose and without fee is hereby granted.
 
-The 15 "bas*.png" images are part of the much larger PngSuite test-set of 
-images, available for developers of PNG supporting software. The 
-complete set, available at http:/www.schaik.com/pngsuite/, contains 
+The 15 "bas*.png" images are part of the much larger PngSuite test-set of
+images, available for developers of PNG supporting software. The
+complete set, available at http:/www.schaik.com/pngsuite/, contains
 a variety of images to test interlacing, gamma settings, ancillary
 chunks, etc.
 
@@ -48,7 +48,7 @@ can use them to test the proper functioning of PNG software.
     ftbwn3p08.png  8-bit paletted, white bKGD
     ftbyn3p08.png  8-bit paletted, yellow bKGD
     ftp0n0g08.png  8-bit grayscale, opaque
-    ftp0n2c08.png  8-bit truecolor, opaque 
+    ftp0n2c08.png  8-bit truecolor, opaque
     ftp0n3p08.png  8-bit paletted, opaque
     ftp1n3p08.png  8-bit paletted, no bKGD
 

contrib/visupng/PngFile.c

@@ -152,29 +152,29 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
 
     Try
     {
-        
+
         // initialize the png structure
-        
+
 #ifdef PNG_STDIO_SUPPORTED
         png_init_io(png_ptr, pfFile);
 #else
         png_set_read_fn(png_ptr, (png_voidp)pfFile, png_read_data);
 #endif
-        
+
         png_set_sig_bytes(png_ptr, 8);
-        
+
         // read all PNG info up to image data
-        
+
         png_read_info(png_ptr, info_ptr);
-        
+
         // get width, height, bit-depth and color-type
-        
+
         png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
             &iColorType, NULL, NULL, NULL);
-        
+
         // expand images of all color-type and bit-depth to 3x8 bit RGB images
         // let the library process things like alpha, transparency, background
-        
+
         if (iBitDepth == 16)
             png_set_strip_16(png_ptr);
         if (iColorType == PNG_COLOR_TYPE_PALETTE)
@@ -186,7 +186,7 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
         if (iColorType == PNG_COLOR_TYPE_GRAY ||
             iColorType == PNG_COLOR_TYPE_GRAY_ALPHA)
             png_set_gray_to_rgb(png_ptr);
-        
+
         // set the background color to draw transparent and alpha images over.
         if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
         {
@@ -199,30 +199,30 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
         {
             pBkgColor = NULL;
         }
-        
+
         // if required set gamma conversion
         if (png_get_gAMA(png_ptr, info_ptr, &dGamma))
             png_set_gamma(png_ptr, (double) 2.2, dGamma);
-        
+
         // after the transformations have been registered update info_ptr data
-        
+
         png_read_update_info(png_ptr, info_ptr);
-        
+
         // get again width, height and the new bit-depth and color-type
-        
+
         png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
             &iColorType, NULL, NULL, NULL);
-        
-        
+
+
         // row_bytes is the width x number of channels
-        
+
         ulRowBytes = png_get_rowbytes(png_ptr, info_ptr);
         ulChannels = png_get_channels(png_ptr, info_ptr);
-        
+
         *piChannels = ulChannels;
-        
+
         // now we can allocate memory to store the image
-        
+
         if (pbImageData)
         {
             free (pbImageData);
@@ -234,33 +234,33 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
             png_error(png_ptr, "Visual PNG: out of memory");
         }
         *ppbImageData = pbImageData;
-        
+
         // and allocate memory for an array of row-pointers
-        
+
         if ((ppbRowPointers = (png_bytepp) malloc((*piHeight)
                             * sizeof(png_bytep))) == NULL)
         {
             png_error(png_ptr, "Visual PNG: out of memory");
         }
-        
+
         // set the individual row-pointers to point at the correct offsets
-        
+
         for (i = 0; i < (*piHeight); i++)
             ppbRowPointers[i] = pbImageData + i * ulRowBytes;
-        
+
         // now we can go ahead and just read the whole image
-        
+
         png_read_image(png_ptr, ppbRowPointers);
-        
+
         // read the additional chunks in the PNG file (not really needed)
-        
+
         png_read_end(png_ptr, NULL);
-        
+
         // and we're done
-        
+
         free (ppbRowPointers);
         ppbRowPointers = NULL;
-        
+
         // yepp, done
     }
 
@@ -269,7 +269,7 @@ BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
         png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 
         *ppbImageData = pbImageData = NULL;
-        
+
         if(ppbRowPointers)
             free (ppbRowPointers);
 
@@ -323,58 +323,58 @@ BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
     Try
     {
         // initialize the png structure
-        
+
 #ifdef PNG_STDIO_SUPPORTED
         png_init_io(png_ptr, pfFile);
 #else
         png_set_write_fn(png_ptr, (png_voidp)pfFile, png_write_data, png_flush);
 #endif
-        
+
         // we're going to write a very simple 3x8 bit RGB image
-        
+
         png_set_IHDR(png_ptr, info_ptr, iWidth, iHeight, ciBitDepth,
             PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
             PNG_FILTER_TYPE_BASE);
-        
+
         // write the file header information
-        
+
         png_write_info(png_ptr, info_ptr);
-        
+
         // swap the BGR pixels in the DiData structure to RGB
-        
+
         png_set_bgr(png_ptr);
-        
+
         // row_bytes is the width x number of channels
-        
+
         ulRowBytes = iWidth * ciChannels;
-        
+
         // we can allocate memory for an array of row-pointers
-        
+
         if ((ppbRowPointers = (png_bytepp) malloc(iHeight * sizeof(png_bytep))) == NULL)
             Throw "Visualpng: Out of memory";
-        
+
         // set the individual row-pointers to point at the correct offsets
-        
+
         for (i = 0; i < iHeight; i++)
             ppbRowPointers[i] = pDiData + i * (((ulRowBytes + 3) >> 2) << 2);
-        
+
         // write out the entire image data in one call
-        
+
         png_write_image (png_ptr, ppbRowPointers);
-        
+
         // write the additional chunks to the PNG file (not really needed)
-        
+
         png_write_end(png_ptr, info_ptr);
-        
+
         // and we're done
-        
+
         free (ppbRowPointers);
         ppbRowPointers = NULL;
-        
+
         // clean up after the write, and free any memory allocated
-        
+
         png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
-        
+
         // yepp, done
     }
 
@@ -389,9 +389,9 @@ BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
 
         return FALSE;
     }
-    
+
     fclose (pfFile);
-    
+
     return TRUE;
 }
 

contrib/visupng/README.txt

@@ -8,8 +8,8 @@ For conditions of distribution and use, see the disclaimer
 and license in png.h
 
 As a PNG .dll demo VisualPng is finished. More features would only hinder
-the program's objective. However, further extensions (like support for other 
-graphics formats) are in development. To get these, or for pre-compiled 
+the program's objective. However, further extensions (like support for other
+graphics formats) are in development. To get these, or for pre-compiled
 binaries, go to "http://www.schaik.com/png/visualpng.html".
 
 ------------------------------------------------------------------------

contrib/visupng/VisualPng.c

@@ -302,23 +302,23 @@ LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
             {
                 if (strcmp (szImgPathName, "") == 0)
                     return 0;
-                
+
                 // load the image from file
-                
+
                 if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
                         &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
                     return 0;
-                
+
                 // invalidate the client area for later update
-                
+
                 InvalidateRect (hwnd, NULL, TRUE);
-                
+
                 // display the PNG into the DIBitmap
-                
+
                 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
                     pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
             }
-            
+
             return 0;
 
         case IDM_FILE_PREVIOUS:
@@ -328,22 +328,22 @@ LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
             if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
                 szImgPathName, NULL))
             {
-                
+
                 if (strcmp (szImgPathName, "") == 0)
                     return 0;
-                
+
                 // load the image from file
-                
+
                 if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
                     &cyImgSize, &cImgChannels, &bkgColor))
                     return 0;
-                
+
                 // invalidate the client area for later update
-                
+
                 InvalidateRect (hwnd, NULL, TRUE);
-                
+
                 // display the PNG into the DIBitmap
-                
+
                 DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
                     pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
             }
@@ -619,29 +619,29 @@ BOOL SearchPngList (
     if (FileCount > 0)
     {
         // get previous entry
-        
+
         if (pstrPrevName != NULL)
         {
             if (*pFileIndex > 0)
                 *pFileIndex -= 1;
             else
                 *pFileIndex = FileCount - 1;
-            
+
             strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
         }
-        
+
         // get next entry
-        
+
         if (pstrNextName != NULL)
         {
             if (*pFileIndex < FileCount - 1)
                 *pFileIndex += 1;
             else
                 *pFileIndex = 0;
-            
+
             strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
         }
-        
+
         return TRUE;
     }
     else

contrib/visupng/resource.h

@@ -12,7 +12,7 @@
 #define IDM_HELP_ABOUT                  40008
 
 // Next default values for new objects
-// 
+//
 #ifdef APSTUDIO_INVOKED
 #ifndef APSTUDIO_READONLY_SYMBOLS
 #define _APS_NEXT_RESOURCE_VALUE        113

example.c

@@ -2,7 +2,7 @@
 #if 0 /* in case someone actually tries to compile this */
 
 /* example.c - an example of using libpng
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.3 [(PENDING RELEASE)]
  * This file has been placed in the public domain by the authors.
  * Maintained 1998-2011 Glenn Randers-Pehrson
  * Maintained 1996, 1997 Andreas Dilger)
@@ -22,6 +22,10 @@
  * see also the programs in the contrib directory.
  */
 
+#define _POSIX_SOURCE 1  /* libpng and zlib are POSIX-compliant.  You may
+                          * change this if your application uses non-POSIX
+                          * extensions. */
+
 #include "png.h"
 
  /* The png_jmpbuf() macro, used in error handling, became available in

libpng-manual.txt

@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.5.3beta03 - April 17, 2011
+ libpng version 1.5.4beta01 - June 14, 2011
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.5.3beta03 - April 17, 2011
+ libpng versions 0.97, January 1998, through 1.5.4beta01 - June 14, 2011
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2011 Glenn Randers-Pehrson
 
@@ -348,21 +348,12 @@ create the structure, so your application should check for that.
        return (ERROR);
     }
 
-    png_infop end_info = png_create_info_struct(png_ptr);
-
-    if (!end_info)
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-          (png_infopp)NULL);
-       return (ERROR);
-    }
-
 If you want to use your own memory allocation routines,
 use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
 png_create_read_struct_2() instead of png_create_read_struct():
 
     png_structp png_ptr = png_create_read_struct_2
-       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
         user_error_fn, user_warning_fn, (png_voidp)
         user_mem_ptr, user_malloc_fn, user_free_fn);
 
@@ -374,7 +365,7 @@ handling and memory alloc/free functions.
 When libpng encounters an error, it expects to longjmp back
 to your routine.  Therefore, you will need to call setjmp and pass
 your png_jmpbuf(png_ptr).  If you read the file from different
-routines, you will need to update the jmpbuf field every time you enter
+routines, you will need to update the longjmp buffer every time you enter
 a new routine that will call a png_*() function.
 
 See your documentation of setjmp/longjmp for your compiler for more
@@ -392,6 +383,9 @@ free any memory.
        return (ERROR);
     }
 
+Pass (png_infopp)NULL instead of &end_info if you didn't create
+an end_info structure.
+
 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
 errors will result in a call to PNG_ABORT() which defaults to abort().
@@ -603,7 +597,7 @@ large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
 Since very few applications really need to process such large images,
 we have imposed an arbitrary 1-million limit on rows and columns.
 Larger images will be rejected immediately with a png_error() call. If
-you wish to override this limit, you can use
+you wish to change this limit, you can use
 
    png_set_user_limits(png_ptr, width_max, height_max);
 
@@ -613,6 +607,10 @@ anyway because of potential buffer overflow conditions).
 
 You should put this statement after you create the PNG structure and
 before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
 If you need to retrieve the limits that are being applied, use
 
    width_max = png_get_user_width_max(png_ptr);
@@ -643,6 +641,229 @@ and you can retrieve the limit with
 Any chunks that would cause either of these limits to be exceeded will
 be ignored.
 
+Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.3 this information can be set before reading the PNG file
+header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.3 test the version number
+and follow the procedures described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value.  You can also specify a default encoding for the PNG file in
+case the required information is missing from the file.  By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+   png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
+
+or you can use the fixed point equivalent:
+
+   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma, PNG_FP_1/screen_gamma);
+
+If you don't know the gamma for you system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB).  If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default.  As of 1.5.3 three special values are available to handle common
+situations:
+
+   PNG_DEFAULT_sRGB: Indicates that the system conforms to the IEC 61966-2-1
+                     standard.  This matches almost all systems.
+   PNG_GAMMA_MAC_18: Indicates that the system is an older (pre Mac OS 10.6)
+                     Apple Macintosh system with the default settings.
+   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates that the
+                     system expects data with no gamma encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and reencode each
+component value whenever arithmetic is performed.  A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information.  Some, but not all, PNG files contain an alpha
+channel.  To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below.)  Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+   png_set_alpha_mode(png_ptr, mode, screen_gamma);
+
+The screen_gamma value is the same as the argument to png_set_gamma, however how
+it affects the output depends on the mode.  png_set_alpha_mode() sets the file
+gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma.  If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+    PNG_ALPHA_PNG: The data is encoded according to the PNG specification.  Red,
+green and blue, or gray, components are gamma encoded color
+values and are not premultiplied by the alpha value.  The
+alpha value is a linear measure of the contribution of the
+pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel.  See the PNG specification for more detail.  It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do your color correction software knows all about alpha (it
+probably doesn't!)
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the standard way
+assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply.  The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding.  Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear.  This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range.  To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD except that
+completely opaque pixels are gamma encoded according to
+the screen_gamma value.  Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and do don't do other arithmetic
+(such as scaling) on the data you get from libpng.  Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD however all component values,
+including the alpha channel are gamma encoded.  This is
+an appropriate format to try if your software, or more
+likely hardware, is totally broken: if it performs
+linear arithmetic directly on gamma encoded values.
+
+In most cases of broken software or hardware the bug in the final display
+manifests as a subtle halo around composited parts of the image.  You may not
+even perceive this as a halo; the composited part of the image may simply appear
+separate from the background, as though it had been cut out of paper and pasted
+on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+       screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally.)  When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+       screen_gamma);
+   png_set_expand_16(png_ptr);
+
+If you are using the high level interface don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+       screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output.  Since this
+mode is libpng specific you also need to write your own composition
+software.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color.  Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+   png_set_background(png_ptr, &background_color,
+       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you.  Because you don't yet know the format of the PNG
+file if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate.  The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format.  (Even low low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface.  For reference the
+settings required are:
+
+8-bit values:
+   PNG_TRANSFORM_STRIP_16 | PNG_EXPAND
+   png_set_expand(png_ptr); png_set_strip_16(png_ptr);
+
+16-bit values:
+   PNG_TRANSFORM_EXPAND_16
+   png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB.  If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.3.  Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read.  Unfortunately this means that prior to libpng-1.5.3 it cannot be
+used with the high level interface.
+
 The high-level read interface
 
 At this point there are two ways to proceed; through the high-level
@@ -653,7 +874,7 @@ you want to do are limited to the following set:
 
     PNG_TRANSFORM_IDENTITY      No transformation
     PNG_TRANSFORM_STRIP_16      Strip 16-bit samples to
-                                8 bits
+                                8-bit
     PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
     PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
                                 samples to bytes
@@ -672,6 +893,7 @@ you want to do are limited to the following set:
     PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
     PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
                                 to RGB (or GA to RGBA)
+    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
 
 (This excludes setting a background color, doing gamma transformation,
 quantizing, and setting filler.)  If this is the case, simply do this:
@@ -740,6 +962,22 @@ call to png_read_info().
 
 This will process all chunks up to but not including the image data.
 
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations.  Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.3 the background color from a bKGd chunk.  This
+damages the information provided by an earlier call to png_set_background
+resulting in expected behavior.  Libpng-1.5.3 no longer does this.
+
+3) The number of significant bits in each component value.  Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk.  This can be modified by
+a later call to png_set_tRNS.
+
 Querying the info structure
 
 Functions are used to get the information from the info_ptr once it
@@ -1103,7 +1341,7 @@ forms:
        converted to microns and back without some loss
        of precision.
 
-For more information, see the png_info definition in png.h and the
+For more information, see the
 PNG specification for chunk contents.  Be careful with trusting
 rowbytes, as some of the transformations could increase the space
 needed to hold a row (expand, filler, gray_to_rgb, etc.).
@@ -1138,17 +1376,20 @@ to handle any special transformations of the image data.  The various
 ways to transform the data will be described in the order that they
 should occur.  This is important, as some of these change the color
 type and/or bit depth of the data, and some others only work on
-certain color types and bit depths.  Even though each transformation
-checks to see if it has data that it can do something with, you should
-make sure to only enable a transformation if it will be valid for the
-data.  For example, don't swap red and blue on grayscale data.
+certain color types and bit depths.
 
-The colors used for the background and transparency values should be
-supplied in the same format/depth as the current image data.  They
-are stored in the same format/depth as the image data in a bKGD or tRNS
-chunk, so this is what libpng expects for this data.  The colors are
-transformed to keep in sync with the image data when an application
-calls the png_read_update_info() routine (see below).
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format.  However some transformations can have an effect
+as a result of a previous transformation.  If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data.  It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
 
 Data will be decoded into the supplied row buffers packed into bytes
 unless the library has been told to transform it into another format.
@@ -1197,27 +1438,25 @@ severe accuracy loss.
       png_set_expand_16(png_ptr);
 
 PNG can have files with 16 bits per channel.  If you only can handle
-8 bits per channel, this will strip the pixels down to 8 bit.
+8 bits per channel, this will strip the pixels down to 8-bit.
 
     if (bit_depth == 16)
        png_set_strip_16(png_ptr);
 
-If, for some reason, you don't need the alpha channel on an image,
-and you want to remove it rather than combining it with the background
-(but the image author certainly had in mind that you *would* combine
-it with the background, so that's what you should probably do):
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
 
     if (color_type & PNG_COLOR_MASK_ALPHA)
        png_set_strip_alpha(png_ptr);
 
-See below for png_set_background(), which does the correct composition on a
-single opaque color.  This is probably what you should do in all cases rather
-than use png_set_strip_alpha() - unless you know for sure that it is the wrong
-thing to do.
+If you strip the alpha channel you need to find some other way of dealing with
+the information.  If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
 
 As of libpng version 1.5.2, almost all useful expansions are supported, the
-major ommissions are convertion of grayscale to indexed images (which can be
-done trivially in the application) and convertion of indexed to grayscale (which
+major ommissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
 can be done by a trivial manipulation of the palette.)
 
 In the following table, the 01 means grayscale with depth<8, 31 means
@@ -1254,8 +1493,7 @@ Within the matrix,
          png_set_expand_gray_1_2_4_to_8() (and by png_set_expand() if there
          is no transparency in the original or the final format).
      "C" means the transformation is obtained by png_set_gray_to_rgb().
-     "G" means the transformation is obtained by png_set_rgb_to_gray() or
-         png_set_rgb_to_Y().
+     "G" means the transformation is obtained by png_set_rgb_to_gray().
      "P" means the transformation is obtained by
          png_set_expand_palette_to_rgb().
      "p" means the transformation is obtained by png_set_packing().
@@ -1347,8 +1585,8 @@ with alpha.
 
     if (color_type == PNG_COLOR_TYPE_RGB ||
         color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_rgb_to_gray_fixed(png_ptr, error_action,
-           int red_weight, int green_weight);
+       png_set_rgb_to_gray(png_ptr, error_action, double red_weight,
+          double green_weight);
 
     error_action = 1: silently do the conversion
 
@@ -1361,122 +1599,89 @@ with alpha.
                       image has any pixel where
                       red != green or red != blue
 
-    red_weight:       weight of red component times 100000
+    red_weight:       weight of red component
 
-    green_weight:     weight of green component times 100000
+    green_weight:     weight of green component
                       If either weight is negative, default
-                      weights (21268, 71514) are used.
+                      weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+    png_set_rgb_to_gray(png_ptr, error_action, png_fixed_point red_weight,
+       png_fixed_point green_weight);
 
 If you have set error_action = 1 or 2, you can
 later check whether the image really was gray, after processing
 the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
 It will return a png_byte that is zero if the image was gray or
-1 if there were any non-gray pixels.  bKGD and sBIT data
+1 if there were any non-gray pixels.  Background and sBIT data
 will be silently converted to grayscale, using the green channel
-data, regardless of the error_action setting.
+data for sBIT, regardless of the error_action setting.
 
-With red_weight+green_weight<=100000,
-the normalized graylevel is computed:
+The default values come from the PNG file cHRM chunk if present, otherwise the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+<http://www.poynton.com/>, in section 9:
 
-    int rw = red_weight * 65536;
-    int gw = green_weight * 65536;
-    int bw = 65536 - (rw + gw);
-    gray = (rw*red + gw*green + bw*blue)/65536;
-
-The default values approximate those recommended in the Charles
-Poynton's Color FAQ, <http://www.inforamp.net/~poynton/>
-Copyright (c) 1998-01-04 Charles Poynton <poynton at inforamp.net>
+   <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
 
     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
 
-Libpng approximates this with integers scaled by 32768:
-
-    Y = (6968 * R + 23434 * G + 2366 * B)/32768
-
 The calculation is done in a linear colorspace, if the image gamma
 can be determined.
 
-If you have a grayscale and you are using png_set_expand_gray_1_2_4_to_8(),
-png_set_expand(), or png_set_gray_to_rgb to change to truecolor or to
-a higher bit-depth, you must either supply the background color as a gray
-value at the original file bit-depth (need_expand = 1) or else supply the
-background color as an RGB triplet at the final, expanded bit depth
-(need_expand = 0).  Similarly, if you are reading a paletted image, you
-must either supply the background color as a palette index (need_expand = 1)
-or as an RGB triplet that may or may not be in the palette (need_expand = 0).
+The png_set_background() function has been described already, it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color.  For compatibility with versions of libpng earlier than
+libpng-1.5.3 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page).  You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamme encoding of the
+color.  The function takes two arguments, background_gamma_mode and need_expand
+to convey this information, however only two combinations are like to be useful:
 
     png_color_16 my_background;
     png_color_16p image_background;
 
     if (png_get_bKGD(png_ptr, info_ptr, &image_background))
        png_set_background(png_ptr, image_background,
-           PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
     else
        png_set_background(png_ptr, &my_background,
-           PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
 
-The png_set_background() function tells libpng to composite images
-with alpha or simple transparency against the supplied background
-color.  If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
-you may use this color, or supply another color more suitable for
-the current display (e.g., the background color from a web page).  You
-need to tell libpng whether the color is in the gamma space of the
-display (PNG_BACKGROUND_GAMMA_SCREEN for colors you supply), the file
-(PNG_BACKGROUND_GAMMA_FILE for colors from the bKGD chunk), or one
-that is neither of these gammas (PNG_BACKGROUND_GAMMA_UNIQUE - I don't
-know why anyone would use this, but it's here).
 
-To properly display PNG images on any kind of system, the application needs
-to know what the display gamma is.  Ideally, the user will know this, and
-the application will allow them to set it.  One method of allowing the user
-to set the display gamma separately for each system is to check for a
-SCREEN_GAMMA or DISPLAY_GAMMA environment variable, which will hopefully be
-correctly set.
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng.  Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.)  However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
 
-Note that display_gamma is the overall gamma correction required to produce
-pleasing results, which depends on the lighting conditions in the surrounding
-environment.  In a dim or brightly lit room, no compensation other than
-the physical gamma exponent of the monitor is needed, while in a dark room
-a slightly smaller exponent is better.
+In the first call the background color has the original bit depth and color type
+of the PNG file.  So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
 
-   double gamma, screen_gamma;
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.3, this is the place to call it.
 
-   if (/* We have a user-defined screen
-       gamma value */)
-   {
-      screen_gamma = user_defined_screen_gamma;
-   }
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
 
-   /* One way that applications can share the same
-      screen gamma value */
-   else if ((gamma_str = getenv("SCREEN_GAMMA"))
-      != NULL)
-   {
-      screen_gamma = (double)atof(gamma_str);
-   }
-
-   /* If we don't have another value */
-   else
-   {
-      screen_gamma = 2.2; /* A good guess for a
-           PC monitor in a bright office or a dim room */
-
-      screen_gamma = 2.0; /* A good guess for a
-           PC monitor in a dark room */
-
-      screen_gamma = 1.7 or 1.0;  /* A good
-           guess for Mac systems */
-   }
-
-The functions png_set_gamma() and its fixed point equivalent
-png_set_gamma_fixed() handle gamma transformations of the data.
-Pass both the file gamma and the current screen_gamma.  If the file does
-not have a gamma value, you can pass one anyway if you have an idea what
-it is (usually 0.45455 is a good guess for GIF images on PCs).  Note
-that file gammas are inverted from screen gammas.  See the discussions
-on gamma in the PNG specification for an excellent description of what
-gamma is, and why all applications should support it.  It is strongly
-recommended that PNG viewers support gamma correction.
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts.  For this reason you must always call it with the PNG file
+value when you call it in this position:
 
    if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
       png_set_gamma(png_ptr, screen_gamma, file_gamma);
@@ -1532,7 +1737,7 @@ This function can also be used to invert grayscale and gray-alpha images:
        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
       png_set_invert_mono(png_ptr);
 
-PNG files store 16 bit pixels in network byte order (big-endian,
+PNG files store 16-bit pixels in network byte order (big-endian,
 ie. most significant bits first).  This code changes the storage to the
 other way (little-endian, i.e. least significant bits first, the
 way PCs store them):
@@ -1824,15 +2029,39 @@ low-level interface, you can finish reading the file.  If you are
 interested in comments or time, which may be stored either before or
 after the image data, you should pass the separate png_info struct if
 you want to keep the comments from before and after the image
-separate.  If you are not interested, you can pass NULL.
+separate.
+
+    png_infop end_info = png_create_info_struct(png_ptr);
+
+    if (!end_info)
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           (png_infopp)NULL);
+       return (ERROR);
+    }
 
    png_read_end(png_ptr, end_info);
 
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+
+   png_read_end(png_ptr, (png_infop)NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
 When you are done, you can free all memory allocated by libpng like this:
 
    png_destroy_read_struct(&png_ptr, &info_ptr,
        &end_info);
 
+or, if you didn't create an end_info structure,
+
+   png_destroy_read_struct(&png_ptr, &info_ptr,
+       (png_infopp)NULL);
+
 It is also possible to individually free the info_ptr members that
 point to libpng-allocated storage with the following function:
 
@@ -2821,7 +3050,7 @@ is required by PNG.
 
     png_set_shift(png_ptr, &sig_bit);
 
-PNG files store 16 bit pixels in network byte order (big-endian,
+PNG files store 16-bit pixels in network byte order (big-endian,
 ie. most significant bits first).  This code would be used if they are
 supplied the other way (little-endian, i.e. least significant bits
 first, the way PCs store them):
@@ -3237,7 +3466,7 @@ the simpler ones to get an idea of how they work.  Try to find a similar
 transformation to the one you want to add and copy off of it.  More details
 can be found in the comments inside the code itself.
 
-Configuring for 16 bit platforms
+Configuring for 16-bit platforms
 
 You will want to look into zconf.h to tell zlib (and thus libpng) that
 it cannot allocate more then 64K at a time.  Even if you can, the memory
@@ -3805,8 +4034,9 @@ absolutely necessary) interlace an image.
 libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
 the application-provided png_longjmp_ptr on the internal, but application
 initialized, jmpbuf.  It is provided as a convenience to avoid the need
-to use the png_jmpbuf macro, which had the unnecessary side effect of
-resetting the internal png_longjmp_ptr value.
+initialized, longjmp buffer.  It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
 
 libpng 1.5.0 includes a complete fixed point API.  By default this is
 present along with the corresponding floating point API.  In general the
@@ -3866,6 +4096,19 @@ In libpng-1.5.3 we reinitialized the zlib stream for each type of data.
 We added five png_set_text_*() functions for setting the parameters to
 use with textual data.
 
+Prior to libpng-1.5.3, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and 16-to-8 scaling is always
+accurate.  This change will result in some different results while
+reading 16-bit images, with none of the pixels being off-by-one any
+longer (see Clause 13.12 of the PNG specification).
+
+Prior to libpng-1.5.3, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them.  Now this function will reduce or
+increase the limits.
+
 B. Changes to the build and configuration of libpng
 
 Details of internal changes to the library code can be found in the CHANGES
@@ -4174,13 +4417,13 @@ Other rules can be inferred by inspecting the libpng source.
 
 XIV. Y2K Compliance in libpng
 
-April 17, 2011
+June 14, 2011
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.5.3beta03 are Y2K compliant.  It is my belief that earlier
+upward through 1.5.4beta01 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that

libpng.3

@@ -1,6 +1,6 @@
-.TH LIBPNG 3 "April 17, 2011"
+.TH LIBPNG 3 "June 14, 2011"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.5.3beta03
+libpng \- Portable Network Graphics (PNG) Reference Library 1.5.4beta01
 .SH SYNOPSIS
 \fI\fB
 
@@ -512,6 +512,14 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.5.3beta03
 
 \fI\fB
 
+\fBvoid png_set_alpha_mode (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, double \fIoutput_gamma\fP\fB);\fP
+
+\fI\fB
+
+\fBvoid png_set_alpha_mode_fixed (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fImode\fP\fB, png_fixed_point \fIoutput_gamma\fP\fB);\fP
+
+\fI\fB
+
 \fBvoid png_set_background (png_structp \fP\fIpng_ptr\fP\fB, png_color_16p \fP\fIbackground_color\fP\fB, int \fP\fIbackground_gamma_code\fP\fB, int \fP\fIneed_expand\fP\fB, double \fIbackground_gamma\fP\fB);\fP
 
 \fI\fB
@@ -943,7 +951,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.5.3beta03 - April 17, 2011
+ libpng version 1.5.4beta01 - June 14, 2011
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2011 Glenn Randers-Pehrson
@@ -954,7 +962,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.5.3beta03 - April 17, 2011
+ libpng versions 0.97, January 1998, through 1.5.4beta01 - June 14, 2011
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2011 Glenn Randers-Pehrson
 
@@ -1291,21 +1299,12 @@ create the structure, so your application should check for that.
        return (ERROR);
     }
 
-    png_infop end_info = png_create_info_struct(png_ptr);
-
-    if (!end_info)
-    {
-       png_destroy_read_struct(&png_ptr, &info_ptr,
-          (png_infopp)NULL);
-       return (ERROR);
-    }
-
 If you want to use your own memory allocation routines,
 use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
 png_create_read_struct_2() instead of png_create_read_struct():
 
     png_structp png_ptr = png_create_read_struct_2
-       (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+        (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
         user_error_fn, user_warning_fn, (png_voidp)
         user_mem_ptr, user_malloc_fn, user_free_fn);
 
@@ -1317,7 +1316,7 @@ handling and memory alloc/free functions.
 When libpng encounters an error, it expects to longjmp back
 to your routine.  Therefore, you will need to call setjmp and pass
 your png_jmpbuf(png_ptr).  If you read the file from different
-routines, you will need to update the jmpbuf field every time you enter
+routines, you will need to update the longjmp buffer every time you enter
 a new routine that will call a png_*() function.
 
 See your documentation of setjmp/longjmp for your compiler for more
@@ -1335,6 +1334,9 @@ free any memory.
        return (ERROR);
     }
 
+Pass (png_infopp)NULL instead of &end_info if you didn't create
+an end_info structure.
+
 If you would rather avoid the complexity of setjmp/longjmp issues,
 you can compile libpng with PNG_NO_SETJMP, in which case
 errors will result in a call to PNG_ABORT() which defaults to abort().
@@ -1546,7 +1548,7 @@ large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
 Since very few applications really need to process such large images,
 we have imposed an arbitrary 1-million limit on rows and columns.
 Larger images will be rejected immediately with a png_error() call. If
-you wish to override this limit, you can use
+you wish to change this limit, you can use
 
    png_set_user_limits(png_ptr, width_max, height_max);
 
@@ -1556,6 +1558,10 @@ anyway because of potential buffer overflow conditions).
 
 You should put this statement after you create the PNG structure and
 before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
 If you need to retrieve the limits that are being applied, use
 
    width_max = png_get_user_width_max(png_ptr);
@@ -1586,6 +1592,229 @@ and you can retrieve the limit with
 Any chunks that would cause either of these limits to be exceeded will
 be ignored.
 
+.SS Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.3 this information can be set before reading the PNG file
+header.  In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.3 test the version number
+and follow the procedures described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value.  You can also specify a default encoding for the PNG file in
+case the required information is missing from the file.  By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+   png_set_gamma(png_ptr, screen_gamma, 1/screen_gamma/*file gamma*/);
+
+or you can use the fixed point equivalent:
+
+   png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma, PNG_FP_1/screen_gamma);
+
+If you don't know the gamma for you system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB).  If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default.  As of 1.5.3 three special values are available to handle common
+situations:
+
+   PNG_DEFAULT_sRGB: Indicates that the system conforms to the IEC 61966-2-1
+                     standard.  This matches almost all systems.
+   PNG_GAMMA_MAC_18: Indicates that the system is an older (pre Mac OS 10.6)
+                     Apple Macintosh system with the default settings.
+   PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates that the
+                     system expects data with no gamma encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and reencode each
+component value whenever arithmetic is performed.  A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information.  Some, but not all, PNG files contain an alpha
+channel.  To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below.)  Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+   png_set_alpha_mode(png_ptr, mode, screen_gamma);
+
+The screen_gamma value is the same as the argument to png_set_gamma, however how
+it affects the output depends on the mode.  png_set_alpha_mode() sets the file
+gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma.  If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+    PNG_ALPHA_PNG: The data is encoded according to the PNG specification.  Red,
+green and blue, or gray, components are gamma encoded color
+values and are not premultiplied by the alpha value.  The
+alpha value is a linear measure of the contribution of the
+pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel.  See the PNG specification for more detail.  It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do your color correction software knows all about alpha (it
+probably doesn't!)
+
+    PNG_ALPHA_STANDARD:  The data libpng produces is encoded in the standard way
+assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply.  The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding.  Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear.  This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range.  To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+    PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD except that
+completely opaque pixels are gamma encoded according to
+the screen_gamma value.  Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and do don't do other arithmetic
+(such as scaling) on the data you get from libpng.  Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+    PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD however all component values,
+including the alpha channel are gamma encoded.  This is
+an appropriate format to try if your software, or more
+likely hardware, is totally broken: if it performs
+linear arithmetic directly on gamma encoded values.
+
+In most cases of broken software or hardware the bug in the final display
+manifests as a subtle halo around composited parts of the image.  You may not
+even perceive this as a halo; the composited part of the image may simply appear
+separate from the background, as though it had been cut out of paper and pasted
+on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+       screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally.)  When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+       screen_gamma);
+   png_set_expand_16(png_ptr);
+
+If you are using the high level interface don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+   png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+       screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output.  Since this
+mode is libpng specific you also need to write your own composition
+software.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color.  Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+   png_set_background(png_ptr, &background_color,
+       PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you.  Because you don't yet know the format of the PNG
+file if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate.  The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format.  (Even low low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface.  For reference the
+settings required are:
+
+8-bit values:
+   PNG_TRANSFORM_STRIP_16 | PNG_EXPAND
+   png_set_expand(png_ptr); png_set_strip_16(png_ptr);
+
+16-bit values:
+   PNG_TRANSFORM_EXPAND_16
+   png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB.  If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.3.  Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read.  Unfortunately this means that prior to libpng-1.5.3 it cannot be
+used with the high level interface.
+
 .SS The high-level read interface
 
 At this point there are two ways to proceed; through the high-level
@@ -1596,7 +1825,7 @@ you want to do are limited to the following set:
 
     PNG_TRANSFORM_IDENTITY      No transformation
     PNG_TRANSFORM_STRIP_16      Strip 16-bit samples to
-                                8 bits
+                                8-bit
     PNG_TRANSFORM_STRIP_ALPHA   Discard the alpha channel
     PNG_TRANSFORM_PACKING       Expand 1, 2 and 4-bit
                                 samples to bytes
@@ -1615,6 +1844,7 @@ you want to do are limited to the following set:
     PNG_TRANSFORM_SWAP_ENDIAN   Byte-swap 16-bit samples
     PNG_TRANSFORM_GRAY_TO_RGB   Expand grayscale samples
                                 to RGB (or GA to RGBA)
+    PNG_TRANSFORM_EXPAND_16     Expand samples to 16 bits
 
 (This excludes setting a background color, doing gamma transformation,
 quantizing, and setting filler.)  If this is the case, simply do this:
@@ -1683,6 +1913,22 @@ call to png_read_info().
 
 This will process all chunks up to but not including the image data.
 
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations.  Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk.  This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.3 the background color from a bKGd chunk.  This
+damages the information provided by an earlier call to png_set_background
+resulting in expected behavior.  Libpng-1.5.3 no longer does this.
+
+3) The number of significant bits in each component value.  Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk.  This can be modified by
+a later call to png_set_tRNS.
+
 .SS Querying the info structure
 
 Functions are used to get the information from the info_ptr once it
@@ -2046,7 +2292,7 @@ forms:
        converted to microns and back without some loss
        of precision.
 
-For more information, see the png_info definition in png.h and the
+For more information, see the
 PNG specification for chunk contents.  Be careful with trusting
 rowbytes, as some of the transformations could increase the space
 needed to hold a row (expand, filler, gray_to_rgb, etc.).
@@ -2081,17 +2327,20 @@ to handle any special transformations of the image data.  The various
 ways to transform the data will be described in the order that they
 should occur.  This is important, as some of these change the color
 type and/or bit depth of the data, and some others only work on
-certain color types and bit depths.  Even though each transformation
-checks to see if it has data that it can do something with, you should
-make sure to only enable a transformation if it will be valid for the
-data.  For example, don't swap red and blue on grayscale data.
+certain color types and bit depths.
 
-The colors used for the background and transparency values should be
-supplied in the same format/depth as the current image data.  They
-are stored in the same format/depth as the image data in a bKGD or tRNS
-chunk, so this is what libpng expects for this data.  The colors are
-transformed to keep in sync with the image data when an application
-calls the png_read_update_info() routine (see below).
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format.  However some transformations can have an effect
+as a result of a previous transformation.  If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data.  It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
 
 Data will be decoded into the supplied row buffers packed into bytes
 unless the library has been told to transform it into another format.
@@ -2140,27 +2389,25 @@ severe accuracy loss.
       png_set_expand_16(png_ptr);
 
 PNG can have files with 16 bits per channel.  If you only can handle
-8 bits per channel, this will strip the pixels down to 8 bit.
+8 bits per channel, this will strip the pixels down to 8-bit.
 
     if (bit_depth == 16)
        png_set_strip_16(png_ptr);
 
-If, for some reason, you don't need the alpha channel on an image,
-and you want to remove it rather than combining it with the background
-(but the image author certainly had in mind that you *would* combine
-it with the background, so that's what you should probably do):
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
 
     if (color_type & PNG_COLOR_MASK_ALPHA)
        png_set_strip_alpha(png_ptr);
 
-See below for png_set_background(), which does the correct composition on a
-single opaque color.  This is probably what you should do in all cases rather
-than use png_set_strip_alpha() - unless you know for sure that it is the wrong
-thing to do.
+If you strip the alpha channel you need to find some other way of dealing with
+the information.  If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
 
 As of libpng version 1.5.2, almost all useful expansions are supported, the
-major ommissions are convertion of grayscale to indexed images (which can be
-done trivially in the application) and convertion of indexed to grayscale (which
+major ommissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
 can be done by a trivial manipulation of the palette.)
 
 In the following table, the 01 means grayscale with depth<8, 31 means
@@ -2197,8 +2444,7 @@ Within the matrix,
          png_set_expand_gray_1_2_4_to_8() (and by png_set_expand() if there
          is no transparency in the original or the final format).
      "C" means the transformation is obtained by png_set_gray_to_rgb().
-     "G" means the transformation is obtained by png_set_rgb_to_gray() or
-         png_set_rgb_to_Y().
+     "G" means the transformation is obtained by png_set_rgb_to_gray().
      "P" means the transformation is obtained by
          png_set_expand_palette_to_rgb().
      "p" means the transformation is obtained by png_set_packing().
@@ -2290,8 +2536,8 @@ with alpha.
 
     if (color_type == PNG_COLOR_TYPE_RGB ||
         color_type == PNG_COLOR_TYPE_RGB_ALPHA)
-       png_set_rgb_to_gray_fixed(png_ptr, error_action,
-           int red_weight, int green_weight);
+       png_set_rgb_to_gray(png_ptr, error_action, double red_weight,
+          double green_weight);
 
     error_action = 1: silently do the conversion
 
@@ -2304,122 +2550,89 @@ with alpha.
                       image has any pixel where
                       red != green or red != blue
 
-    red_weight:       weight of red component times 100000
+    red_weight:       weight of red component
 
-    green_weight:     weight of green component times 100000
+    green_weight:     weight of green component
                       If either weight is negative, default
-                      weights (21268, 71514) are used.
+                      weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+    png_set_rgb_to_gray(png_ptr, error_action, png_fixed_point red_weight,
+       png_fixed_point green_weight);
 
 If you have set error_action = 1 or 2, you can
 later check whether the image really was gray, after processing
 the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
 It will return a png_byte that is zero if the image was gray or
-1 if there were any non-gray pixels.  bKGD and sBIT data
+1 if there were any non-gray pixels.  Background and sBIT data
 will be silently converted to grayscale, using the green channel
-data, regardless of the error_action setting.
+data for sBIT, regardless of the error_action setting.
 
-With red_weight+green_weight<=100000,
-the normalized graylevel is computed:
+The default values come from the PNG file cHRM chunk if present, otherwise the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+<http://www.poynton.com/>, in section 9:
 
-    int rw = red_weight * 65536;
-    int gw = green_weight * 65536;
-    int bw = 65536 - (rw + gw);
-    gray = (rw*red + gw*green + bw*blue)/65536;
-
-The default values approximate those recommended in the Charles
-Poynton's Color FAQ, <http://www.inforamp.net/~poynton/>
-Copyright (c) 1998-01-04 Charles Poynton <poynton at inforamp.net>
+   <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
 
     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
 
-Libpng approximates this with integers scaled by 32768:
-
-    Y = (6968 * R + 23434 * G + 2366 * B)/32768
-
 The calculation is done in a linear colorspace, if the image gamma
 can be determined.
 
-If you have a grayscale and you are using png_set_expand_gray_1_2_4_to_8(),
-png_set_expand(), or png_set_gray_to_rgb to change to truecolor or to
-a higher bit-depth, you must either supply the background color as a gray
-value at the original file bit-depth (need_expand = 1) or else supply the
-background color as an RGB triplet at the final, expanded bit depth
-(need_expand = 0).  Similarly, if you are reading a paletted image, you
-must either supply the background color as a palette index (need_expand = 1)
-or as an RGB triplet that may or may not be in the palette (need_expand = 0).
+The png_set_background() function has been described already, it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color.  For compatibility with versions of libpng earlier than
+libpng-1.5.3 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page).  You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamme encoding of the
+color.  The function takes two arguments, background_gamma_mode and need_expand
+to convey this information, however only two combinations are like to be useful:
 
     png_color_16 my_background;
     png_color_16p image_background;
 
     if (png_get_bKGD(png_ptr, info_ptr, &image_background))
        png_set_background(png_ptr, image_background,
-           PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+           PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
     else
        png_set_background(png_ptr, &my_background,
-           PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
+           PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
 
-The png_set_background() function tells libpng to composite images
-with alpha or simple transparency against the supplied background
-color.  If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
-you may use this color, or supply another color more suitable for
-the current display (e.g., the background color from a web page).  You
-need to tell libpng whether the color is in the gamma space of the
-display (PNG_BACKGROUND_GAMMA_SCREEN for colors you supply), the file
-(PNG_BACKGROUND_GAMMA_FILE for colors from the bKGD chunk), or one
-that is neither of these gammas (PNG_BACKGROUND_GAMMA_UNIQUE - I don't
-know why anyone would use this, but it's here).
 
-To properly display PNG images on any kind of system, the application needs
-to know what the display gamma is.  Ideally, the user will know this, and
-the application will allow them to set it.  One method of allowing the user
-to set the display gamma separately for each system is to check for a
-SCREEN_GAMMA or DISPLAY_GAMMA environment variable, which will hopefully be
-correctly set.
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng.  Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.)  However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
 
-Note that display_gamma is the overall gamma correction required to produce
-pleasing results, which depends on the lighting conditions in the surrounding
-environment.  In a dim or brightly lit room, no compensation other than
-the physical gamma exponent of the monitor is needed, while in a dark room
-a slightly smaller exponent is better.
+In the first call the background color has the original bit depth and color type
+of the PNG file.  So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
 
-   double gamma, screen_gamma;
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.3, this is the place to call it.
 
-   if (/* We have a user-defined screen
-       gamma value */)
-   {
-      screen_gamma = user_defined_screen_gamma;
-   }
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode().  (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
 
-   /* One way that applications can share the same
-      screen gamma value */
-   else if ((gamma_str = getenv("SCREEN_GAMMA"))
-      != NULL)
-   {
-      screen_gamma = (double)atof(gamma_str);
-   }
-
-   /* If we don't have another value */
-   else
-   {
-      screen_gamma = 2.2; /* A good guess for a
-           PC monitor in a bright office or a dim room */
-
-      screen_gamma = 2.0; /* A good guess for a
-           PC monitor in a dark room */
-
-      screen_gamma = 1.7 or 1.0;  /* A good
-           guess for Mac systems */
-   }
-
-The functions png_set_gamma() and its fixed point equivalent
-png_set_gamma_fixed() handle gamma transformations of the data.
-Pass both the file gamma and the current screen_gamma.  If the file does
-not have a gamma value, you can pass one anyway if you have an idea what
-it is (usually 0.45455 is a good guess for GIF images on PCs).  Note
-that file gammas are inverted from screen gammas.  See the discussions
-on gamma in the PNG specification for an excellent description of what
-gamma is, and why all applications should support it.  It is strongly
-recommended that PNG viewers support gamma correction.
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts.  For this reason you must always call it with the PNG file
+value when you call it in this position:
 
    if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
       png_set_gamma(png_ptr, screen_gamma, file_gamma);
@@ -2475,7 +2688,7 @@ This function can also be used to invert grayscale and gray-alpha images:
        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
       png_set_invert_mono(png_ptr);
 
-PNG files store 16 bit pixels in network byte order (big-endian,
+PNG files store 16-bit pixels in network byte order (big-endian,
 ie. most significant bits first).  This code changes the storage to the
 other way (little-endian, i.e. least significant bits first, the
 way PCs store them):
@@ -2767,15 +2980,39 @@ low-level interface, you can finish reading the file.  If you are
 interested in comments or time, which may be stored either before or
 after the image data, you should pass the separate png_info struct if
 you want to keep the comments from before and after the image
-separate.  If you are not interested, you can pass NULL.
+separate.
+
+    png_infop end_info = png_create_info_struct(png_ptr);
+
+    if (!end_info)
+    {
+       png_destroy_read_struct(&png_ptr, &info_ptr,
+           (png_infopp)NULL);
+       return (ERROR);
+    }
 
    png_read_end(png_ptr, end_info);
 
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+
+   png_read_end(png_ptr, (png_infop)NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
 When you are done, you can free all memory allocated by libpng like this:
 
    png_destroy_read_struct(&png_ptr, &info_ptr,
        &end_info);
 
+or, if you didn't create an end_info structure,
+
+   png_destroy_read_struct(&png_ptr, &info_ptr,
+       (png_infopp)NULL);
+
 It is also possible to individually free the info_ptr members that
 point to libpng-allocated storage with the following function:
 
@@ -3764,7 +4001,7 @@ is required by PNG.
 
     png_set_shift(png_ptr, &sig_bit);
 
-PNG files store 16 bit pixels in network byte order (big-endian,
+PNG files store 16-bit pixels in network byte order (big-endian,
 ie. most significant bits first).  This code would be used if they are
 supplied the other way (little-endian, i.e. least significant bits
 first, the way PCs store them):
@@ -4180,7 +4417,7 @@ the simpler ones to get an idea of how they work.  Try to find a similar
 transformation to the one you want to add and copy off of it.  More details
 can be found in the comments inside the code itself.
 
-.SS Configuring for 16 bit platforms
+.SS Configuring for 16-bit platforms
 
 You will want to look into zconf.h to tell zlib (and thus libpng) that
 it cannot allocate more then 64K at a time.  Even if you can, the memory
@@ -4748,8 +4985,9 @@ absolutely necessary) interlace an image.
 libpng 1.5.0 adds an API png_longjmp(png_ptr, value).  This API calls
 the application-provided png_longjmp_ptr on the internal, but application
 initialized, jmpbuf.  It is provided as a convenience to avoid the need
-to use the png_jmpbuf macro, which had the unnecessary side effect of
-resetting the internal png_longjmp_ptr value.
+initialized, longjmp buffer.  It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
 
 libpng 1.5.0 includes a complete fixed point API.  By default this is
 present along with the corresponding floating point API.  In general the
@@ -4809,6 +5047,19 @@ In libpng-1.5.3 we reinitialized the zlib stream for each type of data.
 We added five png_set_text_*() functions for setting the parameters to
 use with textual data.
 
+Prior to libpng-1.5.3, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and 16-to-8 scaling is always
+accurate.  This change will result in some different results while
+reading 16-bit images, with none of the pixels being off-by-one any
+longer (see Clause 13.12 of the PNG specification).
+
+Prior to libpng-1.5.3, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them.  Now this function will reduce or
+increase the limits.
+
 B. Changes to the build and configuration of libpng
 
 Details of internal changes to the library code can be found in the CHANGES
@@ -5117,13 +5368,13 @@ Other rules can be inferred by inspecting the libpng source.
 
 .SH XIV. Y2K Compliance in libpng
 
-April 17, 2011
+June 14, 2011
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
 
 This is your unofficial assurance that libpng from version 0.71 and
-upward through 1.5.3beta03 are Y2K compliant.  It is my belief that earlier
+upward through 1.5.4beta01 are Y2K compliant.  It is my belief that earlier
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that
@@ -5312,7 +5563,10 @@ the first widely used release:
  1.5.2beta01-03      15    10502  15.so.15.2[.0]
  1.5.2rc01-03        15    10502  15.so.15.2[.0]
  1.5.2               15    10502  15.so.15.2[.0]
- 1.5.3beta01-03      15    10503  15.so.15.3[.0]
+ 1.5.3beta01-10      15    10503  15.so.15.3[.0]
+ 1.5.3rc01-02        15    10503  15.so.15.3[.0]
+ 1.5.3beta11 [no 1.5.3] 15 10503  15.so.15.3[.0]
+ 1.5.4beta01         15    10504  15.so.15.4[.0]
 
 Henceforth the source version will match the shared-library minor
 and patch numbers; the shared-library major version number will be
@@ -5369,7 +5623,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.5.3beta03 - April 17, 2011:
+Libpng version 1.5.4beta01 - June 14, 2011:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -5392,7 +5646,7 @@ this sentence.
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.5.3beta03, April 17, 2011, are
+libpng versions 1.2.6, August 15, 2004, through 1.5.4beta01, June 14, 2011, are
 Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -5491,7 +5745,7 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-April 17, 2011
+June 14, 2011
 
 .\" end of man page
 

libpngpf.3

@@ -1,6 +1,6 @@
-.TH LIBPNGPF 3 "April 17, 2011"
+.TH LIBPNGPF 3 "June 14, 2011"
 .SH NAME
-libpng \- Portable Network Graphics (PNG) Reference Library 1.5.3beta03
+libpng \- Portable Network Graphics (PNG) Reference Library 1.5.4beta01
 (private functions)
 .SH SYNOPSIS
 \fB#include \fI"pngpriv.h"
@@ -18,11 +18,9 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.5.3beta03
 \fI\fB
 
 .SH DESCRIPTION
-The functions previously listed here are  used privately by libpng
+The functions previously listed here are used privately by libpng
 and are not recommended for use by applications.  They are
-not "exported" to applications using shared libraries.  They
-are listed alphabetically here as an aid to libpng maintainers.
-See pngpriv.h for more information on these functions.
+not "exported" to applications using shared libraries.
 
 .SH SEE ALSO
 .BR "png"(5), " libpng"(3), " zlib"(3), " deflate"(5), " " and " zlib"(5)

png.5

@@ -1,4 +1,4 @@
-.TH PNG 5 "April 17, 2011"
+.TH PNG 5 "June 14, 2011"
 .SH NAME
 png \- Portable Network Graphics (PNG) format
 .SH DESCRIPTION

png.c

@@ -1,7 +1,7 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.3 [(PENDING RELEASE)]
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -14,7 +14,7 @@
 #include "pngpriv.h"
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_5_3beta03 Your_png_h_is_not_version_1_5_3beta03;
+typedef png_libpng_version_1_5_4beta01 Your_png_h_is_not_version_1_5_4beta01;
 
 /* Tells libpng that we have already handled the first "num_bytes" bytes
  * of the PNG file signature.  If the PNG data is embedded into another
@@ -137,6 +137,61 @@ png_calculate_crc(png_structp png_ptr, png_const_bytep ptr, png_size_t length)
       png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
 }
 
+/* Check a user supplied version number, called from both read and write
+ * functions that create a png_struct
+ */
+int
+png_user_version_check(png_structp png_ptr, png_const_charp user_png_ver)
+{
+   if (user_png_ver)
+   {
+      int i = 0;
+
+      do
+      {
+         if (user_png_ver[i] != png_libpng_ver[i])
+            png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+      } while (png_libpng_ver[i++]);
+   }
+
+   else
+      png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+
+   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
+   {
+     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
+      * we must recompile any applications that use any older library version.
+      * For versions after libpng 1.0, we will be compatible, so we need
+      * only check the first digit.
+      */
+      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
+          (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
+          (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
+      {
+#ifdef PNG_WARNINGS_SUPPORTED
+         size_t pos = 0;
+         char m[128];
+
+         pos = png_safecat(m, sizeof m, pos, "Application built with libpng-");
+         pos = png_safecat(m, sizeof m, pos, user_png_ver);
+         pos = png_safecat(m, sizeof m, pos, " but running with ");
+         pos = png_safecat(m, sizeof m, pos, png_libpng_ver);
+
+         png_warning(png_ptr, m);
+#endif
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+         png_ptr->flags = 0;
+#endif
+
+         return 0;
+      }
+   }
+
+   /* Success return. */
+   return 1;
+}
+
 /* Allocate the memory for an info_struct for the application.  We don't
  * really need the png_ptr, but it could potentially be useful in the
  * future.  This should be used in favour of malloc(png_sizeof(png_info))
@@ -291,12 +346,10 @@ png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
    /* Free any sCAL entry */
    if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
    {
-#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
       png_free(png_ptr, info_ptr->scal_s_width);
       png_free(png_ptr, info_ptr->scal_s_height);
       info_ptr->scal_s_width = NULL;
       info_ptr->scal_s_height = NULL;
-#endif
       info_ptr->valid &= ~PNG_INFO_sCAL;
    }
 #endif
@@ -518,28 +571,37 @@ png_convert_to_rfc1123(png_structp png_ptr, png_const_timep ptime)
    if (png_ptr == NULL)
       return (NULL);
 
-   if (png_ptr->time_buffer == NULL)
    {
-      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
-         png_sizeof(char)));
+      size_t pos = 0;
+      char number_buf[5]; /* enough for a four digit year */
+
+#     define APPEND_STRING(string)\
+         pos = png_safecat(png_ptr->time_buffer, sizeof png_ptr->time_buffer,\
+            pos, (string))
+#     define APPEND_NUMBER(format, value)\
+         APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
+#     define APPEND(ch)\
+         if (pos < (sizeof png_ptr->time_buffer)-1)\
+            png_ptr->time_buffer[pos++] = (ch)
+
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day % 32);
+      APPEND(' ');
+      APPEND_STRING(short_months[(ptime->month - 1) % 12]);
+      APPEND(' ');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
+      APPEND(' ');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour % 24);
+      APPEND(':');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute % 60);
+      APPEND(':');
+      APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second % 61);
+      APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
+
+#     undef APPEND
+#     undef APPEND_NUMBER
+#     undef APPEND_STRING
    }
 
-#    ifdef USE_FAR_KEYWORD
-   {
-      char near_time_buf[29];
-      png_snprintf6(near_time_buf, 29, "%d %s %d %02d:%02d:%02d +0000",
-          ptime->day % 32, short_months[(ptime->month - 1) % 12],
-          ptime->year, ptime->hour % 24, ptime->minute % 60,
-          ptime->second % 61);
-      png_memcpy(png_ptr->time_buffer, near_time_buf,
-          29*png_sizeof(char));
-   }
-#    else
-   png_snprintf6(png_ptr->time_buffer, 29, "%d %s %d %02d:%02d:%02d +0000",
-       ptime->day % 32, short_months[(ptime->month - 1) % 12],
-       ptime->year, ptime->hour % 24, ptime->minute % 60,
-       ptime->second % 61);
-#    endif
    return png_ptr->time_buffer;
 }
 #  endif /* PNG_TIME_RFC1123_SUPPORTED */
@@ -555,13 +617,13 @@ png_get_copyright(png_const_structp png_ptr)
 #else
 #  ifdef __STDC__
    return PNG_STRING_NEWLINE \
-     "libpng version 1.5.3beta03 - April 17, 2011" PNG_STRING_NEWLINE \
+     "libpng version 1.5.4beta01 - June 14, 2011" PNG_STRING_NEWLINE \
      "Copyright (c) 1998-2011 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
      "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
      "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
      PNG_STRING_NEWLINE;
 #  else
-      return "libpng version 1.5.3beta03 - April 17, 2011\
+      return "libpng version 1.5.4beta01 - June 14, 2011\
       Copyright (c) 1998-2011 Glenn Randers-Pehrson\
       Copyright (c) 1996-1997 Andreas Dilger\
       Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
@@ -681,6 +743,13 @@ png_check_cHRM_fixed(png_structp png_ptr,
    if (png_ptr == NULL)
       return 0;
 
+   /* (x,y,z) values are first limited to 0..100000 (PNG_FP_1), the white
+    * y must also be greater than 0.  To test for the upper limit calculate
+    * (PNG_FP_1-y) - x must be <= to this for z to be >= 0 (and the expression
+    * cannot overflow.)  At this point we know x and y are >= 0 and (x+y) is
+    * <= PNG_FP_1.  The previous test on PNG_MAX_UINT_31 is removed because it
+    * pointless (and it produces compiler warnings!)
+    */
    if (white_x < 0 || white_y <= 0 ||
          red_x < 0 ||   red_y <  0 ||
        green_x < 0 || green_y <  0 ||
@@ -690,38 +759,26 @@ png_check_cHRM_fixed(png_structp png_ptr,
         "Ignoring attempt to set negative chromaticity value");
       ret = 0;
    }
-   if (white_x > (png_fixed_point)PNG_UINT_31_MAX ||
-       white_y > (png_fixed_point)PNG_UINT_31_MAX ||
-         red_x > (png_fixed_point)PNG_UINT_31_MAX ||
-         red_y > (png_fixed_point)PNG_UINT_31_MAX ||
-       green_x > (png_fixed_point)PNG_UINT_31_MAX ||
-       green_y > (png_fixed_point)PNG_UINT_31_MAX ||
-        blue_x > (png_fixed_point)PNG_UINT_31_MAX ||
-        blue_y > (png_fixed_point)PNG_UINT_31_MAX )
-   {
-      png_warning(png_ptr,
-        "Ignoring attempt to set chromaticity value exceeding 21474.83");
-      ret = 0;
-   }
-   if (white_x > 100000L - white_y)
+   /* And (x+y) must be <= PNG_FP_1 (so z is >= 0) */
+   if (white_x > PNG_FP_1 - white_y)
    {
       png_warning(png_ptr, "Invalid cHRM white point");
       ret = 0;
    }
 
-   if (red_x > 100000L - red_y)
+   if (red_x > PNG_FP_1 - red_y)
    {
       png_warning(png_ptr, "Invalid cHRM red point");
       ret = 0;
    }
 
-   if (green_x > 100000L - green_y)
+   if (green_x > PNG_FP_1 - green_y)
    {
       png_warning(png_ptr, "Invalid cHRM green point");
       ret = 0;
    }
 
-   if (blue_x > 100000L - blue_y)
+   if (blue_x > PNG_FP_1 - blue_y)
    {
       png_warning(png_ptr, "Invalid cHRM blue point");
       ret = 0;
@@ -763,7 +820,7 @@ png_check_IHDR(png_structp png_ptr,
    }
 
 #  ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   if (width > png_ptr->user_width_max || width > PNG_USER_WIDTH_MAX)
+   if (width > png_ptr->user_width_max)
 
 #  else
    if (width > PNG_USER_WIDTH_MAX)
@@ -774,7 +831,7 @@ png_check_IHDR(png_structp png_ptr,
    }
 
 #  ifdef PNG_SET_USER_LIMITS_SUPPORTED
-   if (height > png_ptr->user_height_max || height > PNG_USER_HEIGHT_MAX)
+   if (height > png_ptr->user_height_max)
 #  else
    if (height > PNG_USER_HEIGHT_MAX)
 #  endif
@@ -1495,7 +1552,7 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
          r /= divisor;
          r = floor(r+.5);
 
-         /* A png_fixed_point is a 32 bit integer. */
+         /* A png_fixed_point is a 32-bit integer. */
          if (r <= 2147483647. && r >= -2147483648.)
          {
             *res = (png_fixed_point)r;
@@ -1540,7 +1597,7 @@ png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
 
          if (s32 < D) /* else overflow */
          {
-            /* s32.s00 is now the 64 bit product, do a standard
+            /* s32.s00 is now the 64-bit product, do a standard
              * division, we know that s32 < D, so the maximum
              * required shift is 31.
              */
@@ -1683,7 +1740,7 @@ png_reciprocal2(png_fixed_point a, png_fixed_point b)
  * 2010: moved from pngset.c) */
 /*
  *    Multiply two 32-bit numbers, V1 and V2, using 32-bit
- *    arithmetic, to produce a 64 bit result in the HI/LO words.
+ *    arithmetic, to produce a 64-bit result in the HI/LO words.
  *
  *                  A B
  *                x C D
@@ -1727,17 +1784,17 @@ png_64bit_product (long v1, long v2, unsigned long *hi_product,
 /* Fixed point gamma.
  *
  * To calculate gamma this code implements fast log() and exp() calls using only
- * fixed point arithmetic.  This code has sufficient precision for either 8 or
- * 16 bit sample values.
+ * fixed point arithmetic.  This code has sufficient precision for either 8-bit
+ * or 16-bit sample values.
  *
  * The tables used here were calculated using simple 'bc' programs, but C double
  * precision floating point arithmetic would work fine.  The programs are given
  * at the head of each table.
  *
- * 8 bit log table
+ * 8-bit log table
  *   This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
- *   255, so it's the base 2 logarithm of a normalized 8 bit floating point
- *   mantissa.  The numbers are 32 bit fractions.
+ *   255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ *   mantissa.  The numbers are 32-bit fractions.
  */
 static png_uint_32
 png_8bit_l2[128] =
@@ -1768,10 +1825,10 @@ png_8bit_l2[128] =
    172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
    24347096U, 0U
 #if 0
-   /* The following are the values for 16 bit tables - these work fine for the 8
-    * bit conversions but produce very slightly larger errors in the 16 bit log
-    * (about 1.2 as opposed to 0.7 absolute error in the final value).  To use
-    * these all the shifts below must be adjusted appropriately.
+   /* The following are the values for 16-bit tables - these work fine for the
+    * 8-bit conversions but produce very slightly larger errors in the 16-bit
+    * log (about 1.2 as opposed to 0.7 absolute error in the final value).  To
+    * use these all the shifts below must be adjusted appropriately.
     */
    65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
    57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
@@ -1814,11 +1871,11 @@ png_log8bit(unsigned int x)
    return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
 }
 
-/* The above gives exact (to 16 binary places) log2 values for 8 bit images,
- * for 16 bit images we use the most significant 8 bits of the 16 bit value to
+/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
+ * for 16-bit images we use the most significant 8 bits of the 16-bit value to
  * get an approximation then multiply the approximation by a correction factor
  * determined by the remaining up to 8 bits.  This requires an additional step
- * in the 16 bit case.
+ * in the 16-bit case.
  *
  * We want log2(value/65535), we have log2(v'/255), where:
  *
@@ -1827,8 +1884,8 @@ png_log8bit(unsigned int x)
  *
  * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
  * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
- * than 258.  The final factor also needs to correct for the fact that our 8 bit
- * value is scaled by 255, whereas the 16 bit values must be scaled by 65535.
+ * than 258.  The final factor also needs to correct for the fact that our 8-bit
+ * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
  *
  * This gives a final formula using a calculated value 'x' which is value/v' and
  * scaling by 65536 to match the above table:
@@ -1838,7 +1895,7 @@ png_log8bit(unsigned int x)
  * Since these numbers are so close to '1' we can use simple linear
  * interpolation between the two end values 256/257 (result -368.61) and 258/257
  * (result 367.179).  The values used below are scaled by a further 64 to give
- * 16 bit precision in the interpolation:
+ * 16-bit precision in the interpolation:
  *
  * Start (256): -23591
  * Zero  (257):      0
@@ -1865,7 +1922,7 @@ png_log16bit(png_uint_32 x)
    if ((x & 0x8000) == 0)
       lg2 += 1, x <<= 1;
 
-   /* Calculate the base logarithm from the top 8 bits as a 28 bit fractional
+   /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
     * value.
     */
    lg2 <<= 28;
@@ -1895,18 +1952,18 @@ png_log16bit(png_uint_32 x)
    return (png_int_32)((lg2 + 2048) >> 12);
 }
 
-/* The 'exp()' case must invert the above, taking a 20 bit fixed point
- * logarithmic value and returning a 16 or 8 bit number as appropriate.  In
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate.  In
  * each case only the low 16 bits are relevant - the fraction - since the
  * integer bits (the top 4) simply determine a shift.
  *
- * The worst case is the 16 bit distinction between 65535 and 65534, this
+ * The worst case is the 16-bit distinction between 65535 and 65534, this
  * requires perhaps spurious accuracty in the decoding of the logarithm to
  * distinguish log2(65535/65534.5) - 10^-5 or 17 bits.  There is little chance
  * of getting this accuracy in practice.
  *
  * To deal with this the following exp() function works out the exponent of the
- * frational part of the logarithm by using an accurate 32 bit value from the
+ * frational part of the logarithm by using an accurate 32-bit value from the
  * top four fractional bits then multiplying in the remaining bits.
  */
 static png_uint_32
@@ -1915,7 +1972,7 @@ png_32bit_exp[16] =
 #  if PNG_DO_BC
       for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; }
 #  endif
-   /* NOTE: the first entry is deliberately set to the maximum 32 bit value. */
+   /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
    4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
    3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
    2553802834U, 2445529972U, 2341847524U, 2242560872U
@@ -1943,7 +2000,7 @@ png_exp(png_fixed_point x)
 {
    if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
    {
-      /* Obtain a 4 bit approximation */
+      /* Obtain a 4-bit approximation */
       png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf];
 
       /* Incorporate the low 12 bits - these decrease the returned value by
@@ -1989,10 +2046,10 @@ png_exp(png_fixed_point x)
 static png_byte
 png_exp8bit(png_fixed_point lg2)
 {
-   /* Get a 32 bit value: */
+   /* Get a 32-bit value: */
    png_uint_32 x = png_exp(lg2);
 
-   /* Convert the 32 bit value to 0..255 by multiplying by 256-1, note that the
+   /* Convert the 32-bit value to 0..255 by multiplying by 256-1, note that the
     * second, rounding, step can't overflow because of the first, subtraction,
     * step.
     */
@@ -2003,10 +2060,10 @@ png_exp8bit(png_fixed_point lg2)
 static png_uint_16
 png_exp16bit(png_fixed_point lg2)
 {
-   /* Get a 32 bit value: */
+   /* Get a 32-bit value: */
    png_uint_32 x = png_exp(lg2);
 
-   /* Convert the 32 bit value to 0..65535 by multiplying by 65536-1: */
+   /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
    x -= x >> 16;
    return (png_uint_16)((x + 32767U) >> 16);
 }
@@ -2059,9 +2116,9 @@ png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
 }
 
 /* This does the right thing based on the bit_depth field of the
- * png_struct, interpreting values as 8 or 16 bit.  While the result
- * is nominally a 16 bit value if bit depth is 8 then the result is
- * 8 bit (as are the arguments.)
+ * png_struct, interpreting values as 8-bit or 16-bit.  While the result
+ * is nominally a 16-bit value if bit depth is 8 then the result is
+ * 8-bit (as are the arguments.)
  */
 png_uint_16 /* PRIVATE */
 png_gamma_correct(png_structp png_ptr, unsigned int value,
@@ -2084,7 +2141,7 @@ png_gamma_significant(png_fixed_point gamma_val)
        gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
 }
 
-/* Internal function to build a single 16 bit table - the table consists of
+/* Internal function to build a single 16-bit table - the table consists of
  * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
  * to shift the input values right (or 16-number_of_signifiant_bits).
  *
@@ -2111,7 +2168,7 @@ png_build_16bit_table(png_structp png_ptr, png_uint_16pp *ptable,
           (png_uint_16p)png_malloc(png_ptr, 256 * png_sizeof(png_uint_16));
 
       /* The 'threshold' test is repeated here because it can arise for one of
-       * the 16 bit tables even if the others don't hit it.
+       * the 16-bit tables even if the others don't hit it.
        */
       if (png_gamma_significant(gamma_val))
       {
@@ -2173,7 +2230,7 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
        (png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p));
 
    /* 'num' is the number of tables and also the number of low bits of low
-    * bits of the input 16 bit value used to select a table.  Each table is
+    * bits of the input 16-bit value used to select a table.  Each table is
     * itself index by the high 8 bits of the value.
     */
    for (i = 0; i < num; i++)
@@ -2183,24 +2240,24 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
    /* 'gamma_val' is set to the reciprocal of the value calculated above, so
     * pow(out,g) is an *input* value.  'last' is the last input value set.
     *
-    * In the loop 'i' is used to find output values.  Since the output is 8
-    * bit there are only 256 possible values.  The tables are set up to
+    * In the loop 'i' is used to find output values.  Since the output is
+    * 8-bit there are only 256 possible values.  The tables are set up to
     * select the closest possible output value for each input by finding
     * the input value at the boundary between each pair of output values
     * and filling the table up to that boundary with the lower output
     * value.
     *
-    * The boundary values are 0.5,1.5..253.5,254.5.  Since these are 9 bit
-    * values the code below uses a 16 bit value in i; the values start at
+    * The boundary values are 0.5,1.5..253.5,254.5.  Since these are 9-bit
+    * values the code below uses a 16-bit value in i; the values start at
     * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
     * entries are filled with 255).  Start i at 128 and fill all 'last'
     * table entries <= 'max'
     */
    last = 0;
-   for (i = 0; i < 255; ++i) /* 8 bit output value */
+   for (i = 0; i < 255; ++i) /* 8-bit output value */
    {
       /* Find the corresponding maximum input value */
-      png_uint_16 out = (png_uint_16)(i * 257U); /* 16 bit output value */
+      png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
 
       /* Find the boundary value in 16 bits: */
       png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
@@ -2223,7 +2280,7 @@ png_build_16to8_table(png_structp png_ptr, png_uint_16pp *ptable,
    }
 }
 
-/* Build a single 8 bit table: same as the 16 bit case but much simpler (and
+/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
  * typically much faster).  Note that libpng currently does no sBIT processing
  * (apparently contrary to the spec) so a 256 entry table is always generated.
  */
@@ -2258,8 +2315,9 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
          png_ptr->screen_gamma) : PNG_FP_1);
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-     if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
+     if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
      {
         png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
             png_reciprocal(png_ptr->gamma));
@@ -2268,7 +2326,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
             png_ptr->screen_gamma > 0 ?  png_reciprocal(png_ptr->screen_gamma) :
             png_ptr->gamma/* Probably doing rgb_to_gray */);
      }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
   }
   else
   {
@@ -2287,7 +2345,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
      else
         sig_bit = png_ptr->sig_bit.gray;
 
-     /* 16 bit gamma code uses this equation:
+     /* 16-bit gamma code uses this equation:
       *
       *   ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
       *
@@ -2302,7 +2360,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
       *
       * So the table 'n' corresponds to all those 'iv' of:
       *
-      *   <all high 8 bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
+      *   <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
       *
       */
      if (sig_bit > 0 && sig_bit < 16U)
@@ -2327,7 +2385,12 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
      png_ptr->gamma_shift = shift;
 
 #ifdef PNG_16BIT_SUPPORTED
-     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
+     /* NOTE: prior to 1.5.3 this test used to include PNG_BACKGROUND (now
+      * PNG_COMPOSE).  This effectively smashed the background calculation for
+      * 16-bit output because the 8-bit table assumes the result will be reduced
+      * to 8 bits.
+      */
+     if (png_ptr->transformations & PNG_16_TO_8)
 #endif
          png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
          png_ptr->screen_gamma > 0 ? png_product2(png_ptr->gamma,
@@ -2341,8 +2404,9 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
 #endif
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-     if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
+     if (png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY))
      {
         png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
             png_reciprocal(png_ptr->gamma));
@@ -2355,7 +2419,7 @@ png_build_gamma_table(png_structp png_ptr, int bit_depth)
             png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
             png_ptr->gamma/* Probably doing rgb_to_gray */);
      }
-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
   }
 }
 #endif /* READ_GAMMA */

png.h

@@ -1,7 +1,7 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng version 1.5.3beta03 - April 17, 2011
+ * libpng version 1.5.4beta01 - June 14, 2011
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -11,7 +11,7 @@
  * Authors and maintainers:
  *   libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
  *   libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
- *   libpng versions 0.97, January 1998, through 1.5.3beta03 - April 17, 2011: Glenn
+ *   libpng versions 0.97, January 1998, through 1.5.4beta01 - June 14, 2011: Glenn
  *   See also "Contributing Authors", below.
  *
  * Note about libpng version numbers:
@@ -150,7 +150,10 @@
  *    1.5.2beta01-03          15    10502  15.so.15.2[.0]
  *    1.5.2rc01-03            15    10502  15.so.15.2[.0]
  *    1.5.2                   15    10502  15.so.15.2[.0]
- *    1.5.3beta01-03          15    10503  15.so.15.3[.0]
+ *    1.5.3beta01-10          15    10503  15.so.15.3[.0]
+ *    1.5.3rc01-02            15    10503  15.so.15.3[.0]
+ *    1.5.3beta11 [no 1.5.3]  15    10503  15.so.15.3[.0]
+ *    1.5.4beta01             15    10504  15.so.15.4[.0]
  *
  *   Henceforth the source version will match the shared-library major
  *   and minor numbers; the shared-library major version number will be
@@ -182,7 +185,7 @@
  *
  * This code is released under the libpng license.
  *
- * libpng versions 1.2.6, August 15, 2004, through 1.5.3beta03, April 17, 2011, are
+ * libpng versions 1.2.6, August 15, 2004, through 1.5.4beta01, June 14, 2011, are
  * Copyright (c) 2004, 2006-2011 Glenn Randers-Pehrson, and are
  * distributed according to the same disclaimer and license as libpng-1.2.5
  * with the following individual added to the list of Contributing Authors:
@@ -294,25 +297,24 @@
  * Y2K compliance in libpng:
  * =========================
  *
- *    April 17, 2011
+ *    June 14, 2011
  *
  *    Since the PNG Development group is an ad-hoc body, we can't make
  *    an official declaration.
  *
  *    This is your unofficial assurance that libpng from version 0.71 and
- *    upward through 1.5.3beta03 are Y2K compliant.  It is my belief that
+ *    upward through 1.5.4beta01 are Y2K compliant.  It is my belief that
  *    earlier versions were also Y2K compliant.
  *
- *    Libpng only has three year fields.  One is a 2-byte unsigned integer
- *    that will hold years up to 65535.  The other two hold the date in text
+ *    Libpng only has two year fields.  One is a 2-byte unsigned integer
+ *    that will hold years up to 65535.  The other holds the date in text
  *    format, and will hold years up to 9999.
  *
  *    The integer is
  *        "png_uint_16 year" in png_time_struct.
  *
- *    The strings are
- *        "png_charp time_buffer" in png_struct and
- *        "near_time_buffer", which is a local character string in png.c.
+ *    The string is
+ *        "png_char time_buffer" in png_struct
  *
  *    There are seven time-related functions:
  *        png.c: png_convert_to_rfc_1123() in png.c
@@ -356,9 +358,9 @@
  */
 
 /* Version information for png.h - this should match the version in png.c */
-#define PNG_LIBPNG_VER_STRING "1.5.3beta03"
+#define PNG_LIBPNG_VER_STRING "1.5.4beta01"
 #define PNG_HEADER_VERSION_STRING \
-     " libpng version 1.5.3beta03 - April 17, 2011\n"
+     " libpng version 1.5.4beta01 - June 14, 2011\n"
 
 #define PNG_LIBPNG_VER_SONUM   15
 #define PNG_LIBPNG_VER_DLLNUM  15
@@ -366,12 +368,12 @@
 /* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
 #define PNG_LIBPNG_VER_MAJOR   1
 #define PNG_LIBPNG_VER_MINOR   5
-#define PNG_LIBPNG_VER_RELEASE 3
+#define PNG_LIBPNG_VER_RELEASE 4
 /* This should match the numeric part of the final component of
  * PNG_LIBPNG_VER_STRING, omitting any leading zero:
  */
 
-#define PNG_LIBPNG_VER_BUILD  03
+#define PNG_LIBPNG_VER_BUILD  01
 
 /* Release Status */
 #define PNG_LIBPNG_BUILD_ALPHA    1
@@ -396,7 +398,7 @@
  * version 1.0.0 was mis-numbered 100 instead of 10000).  From
  * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release
  */
-#define PNG_LIBPNG_VER 10503 /* 1.5.3 */
+#define PNG_LIBPNG_VER 10504 /* 1.5.4 */
 
 /* Library configuration: these options cannot be changed after
  * the library has been built.
@@ -518,7 +520,7 @@ extern "C" {
 /* This triggers a compiler error in png.c, if png.c and png.h
  * do not agree upon the version number.
  */
-typedef char* png_libpng_version_1_5_3beta03;
+typedef char* png_libpng_version_1_5_4beta01;
 
 /* Three color definitions.  The order of the red, green, and blue, (and the
  * exact size) is not important, although the size of the fields need to
@@ -666,12 +668,24 @@ typedef struct png_unknown_chunk_t
     /* libpng-using applications should NOT directly modify this byte. */
     png_byte location; /* mode of operation at read time */
 }
+
+
 png_unknown_chunk;
 typedef png_unknown_chunk FAR * png_unknown_chunkp;
 typedef PNG_CONST png_unknown_chunk FAR * png_const_unknown_chunkp;
 typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
 #endif
 
+/* Values for the unknown chunk location byte */
+
+#define PNG_HAVE_IHDR  0x01
+#define PNG_HAVE_PLTE  0x02
+#define PNG_AFTER_IDAT 0x08
+
+/* The complete definition of png_info has, as of libpng-1.5.0,
+ * been moved into a separate header file that is not accessible to
+ * applications.  Read libpng-manual.txt or libpng.3 for more info.
+ */
 typedef struct png_info_def png_info;
 typedef png_info FAR * png_infop;
 typedef PNG_CONST png_info FAR * png_const_infop;
@@ -687,6 +701,8 @@ typedef png_info FAR * FAR * png_infopp;
  */
 #define PNG_FP_1    100000
 #define PNG_FP_HALF  50000
+#define PNG_FP_MAX  ((png_fixed_point)0x7fffffffL)
+#define PNG_FP_MIN  (-PNG_FP_MAX)
 
 /* These describe the color_type field in png_info. */
 /* color type masks */
@@ -793,6 +809,14 @@ typedef struct png_row_info_struct
 typedef png_row_info FAR * png_row_infop;
 typedef png_row_info FAR * FAR * png_row_infopp;
 
+/* The complete definition of png_struct has, as of libpng-1.5.0,
+ * been moved into a separate header file that is not accessible to
+ * applications.  Read libpng-manual.txt or libpng.3 for more info.
+ */
+typedef struct png_struct_def png_struct;
+typedef PNG_CONST png_struct FAR * png_const_structp;
+typedef png_struct FAR * png_structp;
+
 /* These are the function types for the I/O functions and for the functions
  * that allow the user to override the default I/O functions with his or her
  * own.  The png_error_ptr type should match that of user-supplied warning
@@ -801,10 +825,6 @@ typedef png_row_info FAR * FAR * png_row_infopp;
  * modify the buffer it is passed. The 'read' function, on the other hand, is
  * expected to return the read data in the buffer.
  */
-typedef struct png_struct_def png_struct;
-typedef PNG_CONST png_struct FAR * png_const_structp;
-typedef png_struct FAR * png_structp;
-
 typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
 typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
 typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
@@ -879,6 +899,8 @@ PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
 #define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
 /* Added to libpng-1.4.0 */
 #define PNG_TRANSFORM_GRAY_TO_RGB   0x2000      /* read only */
+/* Added to libpng-1.5.3 */
+#define PNG_TRANSFORM_EXPAND_16     0x4000      /* read only */
 
 /* Flags for MNG supported features */
 #define PNG_FLAG_MNG_EMPTY_PLTE     0x01
@@ -1073,7 +1095,7 @@ PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structp png_ptr));
 #endif
 
 #ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* Expand to 16 bit channels, forces conversion of palette to RGB and expansion
+/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
  * of a tRNS chunk if present.
  */
 PNG_EXPORT(221, void, png_set_expand_16, (png_structp png_ptr));
@@ -1100,8 +1122,219 @@ PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structp
     png_ptr));
 #endif
 
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
 PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
     png_colorp palette));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* How the alpha channel is interpreted - this affects how the color channels of
+ * a PNG file are returned when an alpha channel, or tRNS chunk in a palette
+ * file, is present.
+ *
+ * This has no effect on the way pixels are written into a PNG output
+ * datastream. The color samples in a PNG datastream are never premultiplied
+ * with the alpha samples.
+ *
+ * The default is to return data according to the PNG specification: the alpha
+ * channel is a linear measure of the contribution of the pixel to the
+ * corresponding composited pixel.  The gamma encoded color channels must be
+ * scaled according to the contribution and to do this it is necessary to undo
+ * the encoding, scale the color values, perform the composition and reencode
+ * the values.  This is the 'PNG' mode.
+ *
+ * The alternative is to 'associate' the alpha with the color information by
+ * storing color channel values that have been scaled by the alpha.  The
+ * advantage is that the color channels can be resampled (the image can be
+ * scaled) in this form.  The disadvantage is that normal practice is to store
+ * linear, not (gamma) encoded, values and this requires 16-bit channels for
+ * still images rather than the 8-bit channels that are just about sufficient if
+ * gamma encoding is used.  In addition all non-transparent pixel values,
+ * including completely opaque ones, must be gamma encoded to produce the final
+ * image.  This is the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' mode (the
+ * latter being the two common names for associated alpha color channels.)
+ *
+ * Since it is not necessary to perform arithmetic on opaque color values so
+ * long as they are not to be resampled and are in the final color space it is
+ * possible to optimize the handling of alpha by storing the opaque pixels in
+ * the PNG format (adjusted for the output color space) while storing partially
+ * opaque pixels in the standard, linear, format.  The accuracy required for
+ * standard alpha composition is relatively low, because the pixels are
+ * isolated, therefore typically the accuracy loss in storing 8-bit linear
+ * values is acceptable.  (This is not true if the alpha channel is used to
+ * simulate transparency over large areas - use 16 bits or the PNG mode in
+ * this case!)  This is the 'OPTIMIZED' mode.  For this mode a pixel is
+ * treated as opaque only if the alpha value is equal to the maximum value.
+ *
+ * The final choice is to gamma encode the alpha channel as well.  This is
+ * broken because, in practice, no implementation that uses this choice
+ * correctly undoes the encoding before handling alpha composition.  Use this
+ * choice only if other serious errors in the software or hardware you use
+ * mandate it; the typical serious error is for dark halos to appear around
+ * opaque areas of the composited PNG image because of arithmetic overflow.
+ *
+ * The API function png_set_alpha_mode specifies which of these choices to use
+ * with an enumerated 'mode' value and the gamma of the required output:
+ */
+#define PNG_ALPHA_PNG           0 /* according to the PNG standard */
+#define PNG_ALPHA_STANDARD      1 /* according to Porter/Duff */
+#define PNG_ALPHA_ASSOCIATED    1 /* as above; this is the normal practice */
+#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+#define PNG_ALPHA_OPTIMIZED     2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+#define PNG_ALPHA_BROKEN        3 /* the alpha channel is gamma encoded */
+
+PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structp png_ptr, int mode,
+    double output_gamma));
+PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structp png_ptr,
+    int mode, png_fixed_point output_gamma));
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* The output_gamma value is a screen gamma in libpng terminology: it expresses
+ * how to decode the output values, not how they are encoded.  The values used
+ * correspond to the normal numbers used to describe the overall gamma of a
+ * computer display system; for example 2.2 for an sRGB conformant system.  The
+ * values are scaled by 100000 in the _fixed version of the API (so 220000 for
+ * sRGB.)
+ *
+ * The inverse of the value is always used to provide a default for the PNG file
+ * encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+ * to override the PNG gamma information.
+ *
+ * When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+ * opaque pixels however pixels with lower alpha values are not encoded,
+ * regardless of the output gamma setting.
+ *
+ * When the standard Porter Duff handling is requested with mode 1 the output
+ * encoding is set to be linear and the output_gamma value is only relevant
+ * as a default for input data that has no gamma information.  The linear output
+ * encoding will be overridden if png_set_gamma() is called - the results may be
+ * highly unexpected!
+ *
+ * The following numbers are derived from the sRGB standard and the research
+ * behind it.  sRGB is defined to be approximated by a PNG gAMA chunk value of
+ * 0.45455 (1/2.2) for PNG.  The value implicitly includes any viewing
+ * correction required to take account of any differences in the color
+ * environment of the original scene and the intended display environment; the
+ * value expresses how to *decode* the image for display, not how the original
+ * data was *encoded*.
+ *
+ * sRGB provides a peg for the PNG standard by defining a viewing environment.
+ * sRGB itself, and earlier TV standards, actually use a more complex transform
+ * (a linear portion then a gamma 2.4 power law) than PNG can express.  (PNG is
+ * limited to simple power laws.)  By saying that an image for direct display on
+ * an sRGB conformant system should be stored with a gAMA chunk value of 45455
+ * (11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+ * makes it possible to derive values for other display systems and
+ * environments.
+ *
+ * The Mac value is deduced from the sRGB based on an assumption that the actual
+ * extra viewing correction used in early Mac display systems was implemented as
+ * a power 1.45 lookup table.
+ *
+ * Any system where a programmable lookup table is used or where the behavior of
+ * the final display device characteristics can be changed requires system
+ * specific code to obtain the current characteristic.  However this can be
+ * difficult and most PNG gamma correction only requires an approximate value.
+ *
+ * By default, if png_set_alpha_mode() is not called, libpng assumes that all
+ * values are unencoded, linear, values and that the output device also has a
+ * linear characteristic.  This is only very rarely correct - it is invariably
+ * better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+ * default if you don't know what the right answer is!
+ *
+ * The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+ * 10.6) which used a correction table to implement a somewhat lower gamma on an
+ * otherwise sRGB system.
+ *
+ * Both these values are reserved (not simple gamma values) in order to allow
+ * more precise correction internally in the future.
+ *
+ * NOTE: the following values can be passed to either the fixed or floating
+ * point APIs, but the floating point API will also accept floating point
+ * values.
+ */
+#define PNG_DEFAULT_sRGB -1       /* sRGB gamma and color space */
+#define PNG_GAMMA_MAC_18 -2       /* Old Mac '1.8' gamma and color space */
+#define PNG_GAMMA_sRGB   220000   /* Television standards--matches sRGB gamma */
+#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
+#endif
+
+/* The following are examples of calls to png_set_alpha_mode to achieve the
+ * required overall gamma correction and, where necessary, alpha
+ * premultiplication.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ *    This is the default libpng handling of the alpha channel - it is not
+ *    pre-multiplied into the color components.  In addition the call states
+ *    that the output is for a sRGB system and causes all PNG files without gAMA
+ *    chunks to be assumed to be encoded using sRGB.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ *    In this case the output is assumed to be something like an sRGB conformant
+ *    display preceeded by a power-law lookup table of power 1.45.  This is how
+ *    early Mac systems behaved.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+ *    This is the classic Jim Blinn approach and will work in academic
+ *    environments where everything is done by the book.  It has the shortcoming
+ *    of assuming that input PNG data with no gamma information is linear - this
+ *    is unlikely to be correct unless the PNG files where generated locally.
+ *    Most of the time the output precision will be so low as to show
+ *    significant banding in dark areas of the image.
+ *
+ * png_set_expand_16(pp);
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+ *    This is a somewhat more realistic Jim Blinn inspired approach.  PNG files
+ *    are assumed to have the sRGB encoding if not marked with a gamma value and
+ *    the output is always 16 bits per component.  This permits accurate scaling
+ *    and processing of the data.  If you know that your input PNG files were
+ *    generated locally you might need to replace PNG_DEFAULT_sRGB with the
+ *    correct value for your system.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+ *    If you just need to composite the PNG image onto an existing background
+ *    and if you control the code that does this you can use the optimization
+ *    setting.  In this case you just copy completely opaque pixels to the
+ *    output.  For pixels that are not completely transparent (you just skip
+ *    those) you do the composition math using png_composite or png_composite_16
+ *    below then encode the resultant 8-bit or 16-bit values to match the output
+ *    encoding.
+ *
+ * Other cases
+ *    If neither the PNG nor the standard linear encoding work for you because
+ *    of the software or hardware you use then you have a big problem.  The PNG
+ *    case will probably result in halos around the image.  The linear encoding
+ *    will probably result in a washed out, too bright, image (it's actually too
+ *    contrasty.)  Try the ALPHA_OPTIMIZED mode above - this will probably
+ *    substantially reduce the halos.  Alternatively try:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+ *    This option will also reduce the halos, but there will be slight dark
+ *    halos round the opaque parts of the image where the background is light.
+ *    In the OPTIMIZED mode the halos will be light halos where the background
+ *    is dark.  Take your pick - the halos are unavoidable unless you can get
+ *    your hardware/software fixed!  (The OPTIMIZED approach is slightly
+ *    faster.)
+ *
+ * When the default gamma of PNG files doesn't match the output gamma.
+ *    If you have PNG files with no gamma information png_set_alpha_mode allows
+ *    you to provide a default gamma, but it also sets the ouput gamma to the
+ *    matching value.  If you know your PNG files have a gamma that doesn't
+ *    match the output you can take advantage of the fact that
+ *    png_set_alpha_mode always sets the output gamma but only sets the PNG
+ *    default if it is not already set:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ *    The first call sets both the default and the output gamma values, the
+ *    second call overrides the output gamma without changing the default.  This
+ *    is easier than achieving the same effect with png_set_gamma.  You must use
+ *    PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+ *    fire if more than one call to png_set_alpha_mode and png_set_background is
+ *    made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+ *    are ignored.
+ */
 
 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
 PNG_EXPORT(36, void, png_set_strip_alpha, (png_structp png_ptr));
@@ -1169,7 +1402,11 @@ PNG_EXPORT(46, void, png_set_invert_mono, (png_structp png_ptr));
 #endif
 
 #ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* Handle alpha and tRNS by replacing with a background color. */
+/* Handle alpha and tRNS by replacing with a background color.  Prior to
+ * libpng-1.5.3 this API must not be called before the PNG file header has been
+ * read.  Doing so will result in unexpected behavior and possible warnings or
+ * errors if the PNG file contains a bKGD chunk.
+ */
 PNG_FP_EXPORT(47, void, png_set_background, (png_structp png_ptr,
     png_const_color_16p background_color, int background_gamma_code,
     int need_expand, double background_gamma));
@@ -1205,12 +1442,22 @@ PNG_EXPORT(49, void, png_set_quantize,
  */
 #define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
 
-/* Handle gamma correction. Screen_gamma=(display_exponent) */
+/* Handle gamma correction. Screen_gamma=(display_exponent).
+ * NOTE: this API simply sets the screen and file gamma values. It will
+ * therefore override the value for gamma in a PNG file if it is called after
+ * the file header has been read - use with care  - call before reading the PNG
+ * file for best results!
+ *
+ * These routines accept the same gamma values as png_set_alpha_mode (described
+ * above).  The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
+ * API (floating point or fixed.)  Notice, however, that the 'file_gamma' value
+ * is the inverse of a 'screen gamma' value.
+ */
 PNG_FP_EXPORT(50, void, png_set_gamma,
     (png_structp png_ptr, double screen_gamma,
-    double default_file_gamma));
+    double override_file_gamma));
 PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structp png_ptr,
-    png_fixed_point screen_gamma, png_fixed_point default_file_gamma));
+    png_fixed_point screen_gamma, png_fixed_point override_file_gamma));
 #endif
 
 #ifdef PNG_WRITE_FLUSH_SUPPORTED
@@ -1385,6 +1632,7 @@ PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
 #define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
 #define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
 
+#ifdef PNG_WRITE_SUPPORTED
 /* Set the library compression level.  Currently, valid values range from
  * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
  * (0 - no compression, 9 - "maximal" compression).  Note that tests have
@@ -1401,13 +1649,17 @@ PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structp png_ptr,
 PNG_EXPORT(71, void, png_set_compression_strategy, (png_structp png_ptr,
     int strategy));
 
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
 PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structp png_ptr,
     int window_bits));
 
 PNG_EXPORT(73, void, png_set_compression_method, (png_structp png_ptr,
     int method));
+#endif
 
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 /* Also set zlib parameters for compressing non-IDAT chunks */
 PNG_EXPORT(222, void, png_set_text_compression_level,
     (png_structp png_ptr, int level));
@@ -1418,12 +1670,15 @@ PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structp png_ptr,
 PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structp png_ptr,
     int strategy));
 
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
 PNG_EXPORT(225, void, png_set_text_compression_window_bits, (png_structp
     png_ptr, int window_bits));
 
 PNG_EXPORT(226, void, png_set_text_compression_method, (png_structp png_ptr,
     int method));
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
 
 /* These next functions are called for input/output, memory, and error
  * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
@@ -1635,6 +1890,7 @@ PNG_EXPORTA(103, void, png_chunk_error, (png_structp png_ptr,
 PNG_EXPORTA(104, void, png_err, (png_structp png_ptr), PNG_NORETURN);
 #endif
 
+#ifdef PNG_WARNINGS_SUPPORTED
 /* Non-fatal error in libpng.  Can continue, but may have a problem. */
 PNG_EXPORT(105, void, png_warning, (png_structp png_ptr,
     png_const_charp warning_message));
@@ -1642,6 +1898,7 @@ PNG_EXPORT(105, void, png_warning, (png_structp png_ptr,
 /* Non-fatal error in libpng, chunk name is prepended to message. */
 PNG_EXPORT(106, void, png_chunk_warning, (png_structp png_ptr,
     png_const_charp warning_message));
+#endif
 
 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
 /* Benign error in libpng.  Can continue, but may have a problem.
@@ -2309,7 +2566,7 @@ PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
  * scripts/symbols.def as well.
  */
 #ifdef PNG_EXPORT_LAST_ORDINAL
-  PNG_EXPORT_LAST_ORDINAL(226);
+  PNG_EXPORT_LAST_ORDINAL(228);
 #endif
 
 #ifdef __cplusplus

pngconf.h

@@ -1,7 +1,7 @@
 
 /* pngconf.h - machine configurable file for libpng
  *
- * libpng version 1.5.3beta03 - April 17, 2011 
+ * libpng version 1.5.4beta01 - June 14, 2011
  *
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

pngerror.c

@@ -1,7 +1,7 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * Last changed in libpng 1.5.1 [February 3, 2011]
+ * Last changed in libpng 1.5.3 [(PENDING RELEASE)]
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -89,15 +89,121 @@ png_error,(png_structp png_ptr, png_const_charp error_message),PNG_NORETURN)
 PNG_FUNCTION(void,PNGAPI
 png_err,(png_structp png_ptr),PNG_NORETURN)
 {
+   /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
+    * erroneously as '\0', instead of the empty string "".  This was
+    * apparently an error, introduced in libpng-1.2.20, and png_default_error
+    * will crash in this case.
+    */
    if (png_ptr != NULL && png_ptr->error_fn != NULL)
-      (*(png_ptr->error_fn))(png_ptr, '\0');
+      (*(png_ptr->error_fn))(png_ptr, "");
 
    /* If the custom handler doesn't exist, or if it returns,
       use the default handler, which will not return. */
-   png_default_error(png_ptr, '\0');
+   png_default_error(png_ptr, "");
 }
 #endif /* PNG_ERROR_TEXT_SUPPORTED */
 
+/* Utility to safely appends strings to a buffer.  This never errors out so
+ * error checking is not required in the caller.
+ */
+size_t
+png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+   png_const_charp string)
+{
+   if (buffer != NULL && pos < bufsize)
+   {
+      if (string != NULL)
+         while (*string != '\0' && pos < bufsize-1)
+           buffer[pos++] = *string++;
+
+      buffer[pos] = '\0';
+   }
+
+   return pos;
+}
+
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.
+ */
+png_charp
+png_format_number(png_const_charp start, png_charp end, int format,
+   png_alloc_size_t number)
+{
+   int count = 0;    /* number of digits output */
+   int mincount = 1; /* minimum number required */
+   int output = 0;   /* digit output (for the fixed point format) */
+
+   *--end = '\0';
+
+   /* This is written so that the loop always runs at least once, even with
+    * number zero.
+    */
+   while (end > start && (number != 0 || count < mincount))
+   {
+
+      static const char digits[] = "0123456789ABCDEF";
+
+      switch (format)
+      {
+         case PNG_NUMBER_FORMAT_fixed:
+            /* Needs five digits (the fraction) */
+            mincount = 5;
+            if (output || number % 10 != 0)
+            {
+               *--end = digits[number % 10];
+               output = 1;
+            }
+            number /= 10;
+            break;
+
+         case PNG_NUMBER_FORMAT_02u:
+            /* Expects at least 2 digits. */
+            mincount = 2;
+            /* fall through */
+
+         case PNG_NUMBER_FORMAT_u:
+            *--end = digits[number % 10];
+            number /= 10;
+            break;
+
+         case PNG_NUMBER_FORMAT_02x:
+            /* This format expects at least two digits */
+            mincount = 2;
+            /* fall through */
+
+         case PNG_NUMBER_FORMAT_x:
+            *--end = digits[number & 0xf];
+            number >>= 4;
+            break;
+
+         default: /* an error */
+            number = 0;
+            break;
+      }
+
+      /* Keep track of the number of digits added */
+      ++count;
+
+      /* Float a fixed number here: */
+      if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start)
+      {
+         /* End of the fraction, but maybe nothing was output?  In that case
+          * drop the decimal point.  If the number is a true zero handle that
+          * here.
+          */
+         if (output)
+            *--end = '.';
+         else if (number == 0) /* and !output */
+            *--end = '0';
+      }
+   }
+
+   return end;
+}
+#endif
+
 #ifdef PNG_WARNINGS_SUPPORTED
 /* This function is called whenever there is a non-fatal error.  This function
  * should not be changed.  If there is a need to handle warnings differently,
@@ -128,6 +234,115 @@ png_warning(png_structp png_ptr, png_const_charp warning_message)
    else
       png_default_warning(png_ptr, warning_message + offset);
 }
+
+/* These functions support 'formatted' warning messages with up to
+ * PNG_WARNING_PARAMETER_COUNT parameters.  In the format string the parameter
+ * is introduced by @<number>, where 'number' starts at 1.  This follows the
+ * standard established by X/Open for internationalizable error messages.
+ */
+void
+png_warning_parameter(png_warning_parameters p, int number,
+   png_const_charp string)
+{
+   if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
+      (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
+}
+
+void
+png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
+   png_alloc_size_t value)
+{
+   char buffer[PNG_NUMBER_BUFFER_SIZE];
+   png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
+}
+
+void
+png_warning_parameter_signed(png_warning_parameters p, int number, int format,
+   png_int_32 value)
+{
+   png_alloc_size_t u;
+   png_charp str;
+   char buffer[PNG_NUMBER_BUFFER_SIZE];
+
+   /* Avoid overflow by doing the negate in a png_alloc_size_t: */
+   u = (png_alloc_size_t)value;
+   if (value < 0)
+      u = ~u + 1;
+
+   str = PNG_FORMAT_NUMBER(buffer, format, u);
+
+   if (value < 0 && str > buffer)
+      *--str = '-';
+
+   png_warning_parameter(p, number, str);
+}
+
+void
+png_formatted_warning(png_structp png_ptr, png_warning_parameters p,
+   png_const_charp message)
+{
+   /* The internal buffer is just 128 bytes - enough for all our messages,
+    * overflow doesn't happen because this code checks!
+    */
+   size_t i;
+   char msg[128];
+
+   for (i=0; i<(sizeof msg)-1 && *message != '\0'; ++i)
+   {
+      if (*message == '@')
+      {
+         int parameter = -1;
+         switch (*++message)
+         {
+            case '1':
+               parameter = 0;
+               break;
+
+            case '2':
+               parameter = 1;
+               break;
+
+            case '\0':
+               continue; /* To break out of the for loop above. */
+
+            default:
+               break;
+         }
+
+         if (parameter >= 0 && parameter < PNG_WARNING_PARAMETER_COUNT)
+         {
+            /* Append this parameter */
+            png_const_charp parm = p[parameter];
+            png_const_charp pend = p[parameter] + (sizeof p[parameter]);
+
+            /* No need to copy the trailing '\0' here, but there is no guarantee
+             * that parm[] has been initialized, so there is no guarantee of a
+             * trailing '\0':
+             */
+            for (; i<(sizeof msg)-1 && parm != '\0' && parm < pend; ++i)
+               msg[i] = *parm++;
+
+            ++message;
+            continue;
+         }
+
+         /* else not a parameter and there is a character after the @ sign; just
+          * copy that.
+          */
+      }
+
+      /* At this point *message can't be '\0', even in the bad parameter case
+       * above where there is a lone '@' at the end of the message string.
+       */
+      msg[i] = *message++;
+   }
+
+   /* i is always less than (sizeof msg), so: */
+   msg[i] = '\0';
+
+   /* And this is the formatted message: */
+   png_warning(png_ptr, msg);
+}
 #endif /* PNG_WARNINGS_SUPPORTED */
 
 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
@@ -185,8 +400,13 @@ png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
    {
       buffer[iout++] = ':';
       buffer[iout++] = ' ';
-      png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
-      buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
+
+      iin = 0;
+      while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+         buffer[iout++] = error_message[iin++];
+
+      /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+      buffer[iout] = '\0';
    }
 }
 #endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
@@ -272,7 +492,7 @@ png_set_longjmp_fn(png_structp png_ptr, png_longjmp_ptr longjmp_fn,
       return NULL;
 
    png_ptr->longjmp_fn = longjmp_fn;
-   return &png_ptr->png_jmpbuf;
+   return &png_ptr->longjmp_buffer;
 }
 #endif
 
@@ -287,7 +507,8 @@ png_default_error,(png_structp png_ptr, png_const_charp error_message),
 {
 #ifdef PNG_CONSOLE_IO_SUPPORTED
 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
-   if (*error_message == PNG_LITERAL_SHARP)
+   /* Check on NULL only added in 1.5.3 */
+   if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
    {
       /* Strip "#nnnn " from beginning of error message. */
       int offset;
@@ -317,11 +538,11 @@ png_default_error,(png_structp png_ptr, png_const_charp error_message),
    else
 #endif
    {
-      fprintf(stderr, "libpng error: %s", error_message);
+      fprintf(stderr, "libpng error: %s", error_message ? error_message :
+         "undefined");
       fprintf(stderr, PNG_STRING_NEWLINE);
    }
-#endif
-#ifndef PNG_CONSOLE_IO_SUPPORTED
+#else
    PNG_UNUSED(error_message) /* Make compiler happy */
 #endif
    png_longjmp(png_ptr, 1);
@@ -335,13 +556,13 @@ png_longjmp,(png_structp png_ptr, int val),PNG_NORETURN)
    {
 #  ifdef USE_FAR_KEYWORD
       {
-         jmp_buf png_jmpbuf;
-         png_memcpy(png_jmpbuf, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
-         png_ptr->longjmp_fn(png_jmpbuf, val);
+         jmp_buf tmp_jmpbuf;
+         png_memcpy(tmp_jmpbuf, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
+         png_ptr->longjmp_fn(tmp_jmpbuf, val);
       }
 
 #  else
-   png_ptr->longjmp_fn(png_ptr->png_jmpbuf, val);
+   png_ptr->longjmp_fn(png_ptr->longjmp_buffer, val);
 #  endif
    }
 #endif
@@ -403,7 +624,7 @@ png_default_warning(png_structp png_ptr, png_const_charp warning_message)
 /* This function is called when the application wants to use another method
  * of handling errors and warnings.  Note that the error function MUST NOT
  * return to the calling routine or serious problems will occur.  The return
- * method used in the default routine calls longjmp(png_ptr->png_jmpbuf, 1)
+ * method used in the default routine calls longjmp(png_ptr->longjmp_buffer, 1)
  */
 void PNGAPI
 png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
@@ -414,7 +635,11 @@ png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
 
    png_ptr->error_ptr = error_ptr;
    png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    png_ptr->warning_fn = warning_fn;
+#else
+   PNG_UNUSED(warning_fn)
+#endif
 }
 
 

pngpread.c

@@ -1026,8 +1026,10 @@ png_push_process_row(png_structp png_ptr)
 
    png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
 
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
    if (png_ptr->transformations)
       png_do_read_transformations(png_ptr);
+#endif
 
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    /* Blow up interlaced rows to full size */

pngpriv.h

@@ -25,6 +25,20 @@
 #ifndef PNGPRIV_H
 #define PNGPRIV_H
 
+/* Feature Test Macros.  The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+
 /* This is required for the definition of abort(), used as a last ditch
  * error handler when all else fails.
  */
@@ -101,12 +115,20 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #  define PNG_ZBUF_SIZE 65536L
 #endif
 
-/* If warnings or errors are turned off the code is disabled
- * or redirected here.
+/* If warnings or errors are turned off the code is disabled or redirected here.
+ * From 1.5.3 functions have been added to allow very limited formatting of
+ * error and warning messages - this code will also be disabled here.
  */
-#ifndef PNG_WARNINGS_SUPPORTED
-#  define png_warning(s1,s2) ((void)0)
-#  define png_chunk_warning(s1,s2) ((void)0)
+#ifdef PNG_WARNINGS_SUPPORTED
+#  define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
+#else
+#  define png_warning(s1,s2) ((void)(s1))
+#  define png_chunk_warning(s1,s2) ((void)(s1))
+#  define png_warning_parameter(p,number,string) ((void)0)
+#  define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
+#  define png_warning_parameter_signed(p,number,format,value) ((void)0)
+#  define png_formatted_warning(pp,p,message) ((void)(pp))
+#  define PNG_WARNING_PARAMETERS(p)
 #endif
 #ifndef PNG_ERROR_TEXT_SUPPORTED
 #  define png_error(s1,s2) png_err(s1)
@@ -200,60 +222,28 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #  define NOCHECK 0
 #  define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
 #  define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
-#  define png_strcpy  _fstrcpy
-#  define png_strncpy _fstrncpy   /* Added to v 1.2.6 */
 #  define png_strlen  _fstrlen
 #  define png_memcmp  _fmemcmp    /* SJT: added */
 #  define png_memcpy  _fmemcpy
 #  define png_memset  _fmemset
-#  define png_sprintf sprintf
 #else
 #  ifdef _WINDOWS_  /* Favor Windows over C runtime fns */
 #    define CVT_PTR(ptr)         (ptr)
 #    define CVT_PTR_NOCHECK(ptr) (ptr)
-#    define png_strcpy  lstrcpyA
-#    define png_strncpy lstrcpynA
 #    define png_strlen  lstrlenA
 #    define png_memcmp  memcmp
 #    define png_memcpy  CopyMemory
 #    define png_memset  memset
-#    define png_sprintf wsprintfA
 #  else
 #    define CVT_PTR(ptr)         (ptr)
 #    define CVT_PTR_NOCHECK(ptr) (ptr)
-#    define png_strcpy  strcpy
-#    define png_strncpy strncpy     /* Added to v 1.2.6 */
 #    define png_strlen  strlen
 #    define png_memcmp  memcmp      /* SJT: added */
 #    define png_memcpy  memcpy
 #    define png_memset  memset
-#    define png_sprintf sprintf
 #  endif
 #endif
 /* End of memory model/platform independent support */
-
-#if !defined(PNG_NO_SNPRINTF) && !defined(__STRICT_ANSI__)
-#  ifdef _MSC_VER
-#    define png_snprintf _snprintf   /* Added to v 1.2.19 */
-#    define png_snprintf2 _snprintf
-#    define png_snprintf6 _snprintf
-#  else
-#    define png_snprintf snprintf   /* Added to v 1.2.19 */
-#    define png_snprintf2 snprintf
-#    define png_snprintf6 snprintf
-#  endif
-#else
-  /* You don't have or don't want to use snprintf().  Caution: Using
-   * sprintf instead of snprintf exposes your application to accidental
-   * or malevolent buffer overflows.  If you don't have snprintf()
-   * as a general rule you should provide one (you can get one from
-   * Portable OpenSSH).
-   */
-#  define png_snprintf(s1,n,fmt,x1) png_sprintf(s1,fmt,x1)
-#  define png_snprintf2(s1,n,fmt,x1,x2) png_sprintf(s1,fmt,x1,x2)
-#  define png_snprintf6(s1,n,fmt,x1,x2,x3,x4,x5,x6) \
-      png_sprintf(s1,fmt,x1,x2,x3,x4,x5,x6)
-#endif
 /* End of 1.5.0beta36 move from pngconf.h */
 
 /* CONSTANTS and UTILITY MACROS
@@ -261,12 +251,14 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
  */
 
 /* Various modes of operation.  Note that after an init, mode is set to
- * zero automatically when the structure is created.
+ * zero automatically when the structure is created.  Three of these
+ * are defined in png.h because they need to be visible to applications
+ * that call png_set_unknown_chunk().
  */
-#define PNG_HAVE_IHDR               0x01
-#define PNG_HAVE_PLTE               0x02
+/* #define PNG_HAVE_IHDR            0x01 (defined in png.h) */
+/* #define PNG_HAVE_PLTE            0x02 (defined in png.h) */
 #define PNG_HAVE_IDAT               0x04
-#define PNG_AFTER_IDAT              0x08 /* Have complete zlib datastream */
+/* #define PNG_AFTER_IDAT           0x08 (defined in png.h) */
 #define PNG_HAVE_IEND               0x10
 #define PNG_HAVE_gAMA               0x20
 #define PNG_HAVE_cHRM               0x40
@@ -277,7 +269,6 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #define PNG_BACKGROUND_IS_GRAY     0x800
 #define PNG_HAVE_PNG_SIGNATURE    0x1000
 #define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
-#define PNG_ZLIB_READY_FOR_ZTXT   0x4000 /* 1: ready for ZTXT; 0: for IDAT */
 
 /* Flags for the transformations the PNG library does on the image data */
 #define PNG_BGR                 0x0001
@@ -287,7 +278,7 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #define PNG_SWAP_BYTES          0x0010
 #define PNG_INVERT_MONO         0x0020
 #define PNG_QUANTIZE            0x0040
-#define PNG_BACKGROUND          0x0080
+#define PNG_COMPOSE             0x0080     /* Was PNG_BACKGROUND */
 #define PNG_BACKGROUND_EXPAND   0x0100
 #define PNG_EXPAND_16           0x0200     /* Added to libpng 1.5.2 */
 #define PNG_16_TO_8             0x0400
@@ -304,7 +295,7 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #define PNG_RGB_TO_GRAY_ERR   0x200000L
 #define PNG_RGB_TO_GRAY_WARN  0x400000L
 #define PNG_RGB_TO_GRAY       0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */
-                       /*     0x800000L     Unused */
+#define PNG_ENCODE_ALPHA      0x800000L  /* Added to libpng-1.5.3 */
 #define PNG_ADD_ALPHA         0x1000000L  /* Added to libpng-1.2.7 */
 #define PNG_EXPAND_tRNS       0x2000000L  /* Added to libpng-1.2.9 */
                        /*   0x4000000L  unused */
@@ -334,9 +325,9 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
 #define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
 #define PNG_FLAG_CRC_CRITICAL_USE         0x0400
 #define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
-                                /*        0x1000  unused */
-                                /*        0x2000  unused */
-                                /*        0x4000  unused */
+#define PNG_FLAG_ASSUME_sRGB              0x1000  /* Added to libpng-1.5.3 */
+#define PNG_FLAG_OPTIMIZE_ALPHA           0x2000  /* Added to libpng-1.5.3 */
+#define PNG_FLAG_DETECT_UNINITIALIZED     0x4000  /* Added to libpng-1.5.3 */
 #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L
 #define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L
 #define PNG_FLAG_LIBRARY_MISMATCH         0x20000L
@@ -461,6 +452,11 @@ PNG_EXTERN png_fixed_point png_fixed PNGARG((png_structp png_ptr, double fp,
 #define PNG_tRNS PNG_CONST png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
 #define PNG_zTXt PNG_CONST png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
 
+/* Gamma values (new at libpng-1.5.3): */
+#define PNG_GAMMA_MAC_OLD 151724  /* Assume '1.8' is really 2.2/1.45! */
+#define PNG_GAMMA_MAC_INVERSE 65909
+#define PNG_GAMMA_sRGB_INVERSE 45455
+
 
 /* Inhibit C++ name-mangling for libpng functions but not for system calls. */
 #ifdef __cplusplus
@@ -473,6 +469,12 @@ extern "C" {
  * be found in the files where the functions are located.
  */
 
+/* Check the user version string for compatibility, returns false if the version
+ * numbers aren't compatible.
+ */
+PNG_EXTERN int png_user_version_check(png_structp png_ptr,
+   png_const_charp user_png_ver);
+
 /* Allocate memory for an internal libpng struct */
 PNG_EXTERN PNG_FUNCTION(png_voidp,png_create_struct,PNGARG((int type)),
    PNG_ALLOCATED);
@@ -735,17 +737,17 @@ PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,
 PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
     png_row_infop row_info));
 
-/* Write out the filtered row. */
-PNG_EXTERN void png_write_filtered_row PNGARG((png_structp png_ptr,
-    png_bytep filtered_row));
 /* Finish a row while reading, dealing with interlacing passes, etc. */
 PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
 
 /* Initialize the row buffers, etc. */
 PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
 /* Optional call to update the users info structure */
 PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
     png_infop info_ptr));
+#endif
 
 /* These are the functions that do the transformations */
 #ifdef PNG_READ_FILLER_SUPPORTED
@@ -848,26 +850,20 @@ PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info,
     png_bytep row, png_const_color_8p bit_depth));
 #endif
 
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-#  ifdef PNG_READ_GAMMA_SUPPORTED
-PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_color_16p trans_color,
-    png_const_color_16p background, png_const_color_16p background_1,
-    png_const_bytep gamma_table, png_const_bytep gamma_from_1,
-    png_const_bytep gamma_to_1, png_const_uint_16pp gamma_16,
-    png_const_uint_16pp gamma_16_from_1, png_const_uint_16pp gamma_16_to_1,
-    int gamma_shift));
-#  else
-PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_color_16p trans_color,
-    png_const_color_16p background));
-#  endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+PNG_EXTERN void png_do_compose PNGARG((png_row_infop row_info,
+    png_bytep row, png_structp png_ptr));
 #endif
 
 #ifdef PNG_READ_GAMMA_SUPPORTED
 PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info,
-    png_bytep row, png_const_bytep gamma_table,
-    png_const_uint_16pp gamma_16_table, int gamma_shift));
+    png_bytep row, png_structp png_ptr));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+PNG_EXTERN void png_do_encode_alpha PNGARG((png_row_infop row_info,
+   png_bytep row, png_structp png_ptr));
 #endif
 
 #ifdef PNG_READ_EXPAND_SUPPORTED
@@ -987,10 +983,16 @@ PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
     png_const_bytep chunk_name));
 
 /* Handle the transformations for reading and writing */
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
 PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr));
+#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
 PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr));
+#endif
 
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
 PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));
+#endif
 
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
@@ -1087,6 +1089,76 @@ PNG_EXTERN PNG_FUNCTION(void, png_fixed_error, (png_structp png_ptr,
    png_const_charp name),PNG_NORETURN);
 #endif
 
+/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
+ * the end.  Always leaves the buffer nul terminated.  Never errors out (and
+ * there is no error code.)
+ */
+PNG_EXTERN size_t png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+    png_const_charp string);
+
+/* Various internal functions to handle formatted warning messages, currently
+ * only implemented for warnings.
+ */
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.  This utility only
+ * does unsigned values.
+ */
+PNG_EXTERN png_charp png_format_number(png_const_charp start, png_charp end,
+   int format, png_alloc_size_t number);
+
+/* Convenience macro that takes an array: */
+#define PNG_FORMAT_NUMBER(buffer,format,number) \
+   png_format_number(buffer, buffer + (sizeof buffer), format, number)
+
+/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
+#define PNG_NUMBER_BUFFER_SIZE 24
+
+/* These are the integer formats currently supported, the name is formed from
+ * the standard printf(3) format string.
+ */
+#define PNG_NUMBER_FORMAT_u     1 /* chose unsigned API! */
+#define PNG_NUMBER_FORMAT_02u   2
+#define PNG_NUMBER_FORMAT_d     1 /* chose signed API! */
+#define PNG_NUMBER_FORMAT_02d   2
+#define PNG_NUMBER_FORMAT_x     3
+#define PNG_NUMBER_FORMAT_02x   4
+#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* New defines and members adding in libpng-1.5.3 */
+#  define PNG_WARNING_PARAMETER_SIZE 32
+#  define PNG_WARNING_PARAMETER_COUNT 8
+
+/* An l-value of this type has to be passed to the APIs below to cache the
+ * values of the parameters to a formatted warning message.
+ */
+typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
+   PNG_WARNING_PARAMETER_SIZE];
+
+PNG_EXTERN void png_warning_parameter(png_warning_parameters p, int number,
+    png_const_charp string);
+    /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
+     * including the trailing '\0'.
+     */
+PNG_EXTERN void png_warning_parameter_unsigned(png_warning_parameters p,
+    int number, int format, png_alloc_size_t value);
+    /* Use png_alloc_size_t because it is an unsigned type as big as any we
+     * need to output.  Use the following for a signed value.
+     */
+PNG_EXTERN void png_warning_parameter_signed(png_warning_parameters p,
+    int number, int format, png_int_32 value);
+
+PNG_EXTERN void png_formatted_warning(png_structp png_ptr,
+    png_warning_parameters p, png_const_charp message);
+    /* 'message' follows the X/Open approach of using @1, @2 to insert
+     * parameters previously supplied using the above functions.  Errors in
+     * specifying the paramters will simple result in garbage substitutions.
+     */
+#endif
+
 /* ASCII to FP interfaces, currently only implemented if sCAL
  * support is required.
  */

pngread.c

@@ -1,7 +1,7 @@
 
 /* pngread.c - read a PNG file
  *
- * Last changed in libpng 1.5.2 [March 31, 2011]
+ * Last changed in libpng 1.5.3 [(PENDING RELEASE)]
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -47,12 +47,10 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
 
 #ifdef PNG_SETJMP_SUPPORTED
 #ifdef USE_FAR_KEYWORD
-   jmp_buf png_jmpbuf;
+   jmp_buf tmp_jmpbuf;
 #endif
 #endif
 
-   int i;
-
    png_debug(1, "in png_create_read_struct");
 
 #ifdef PNG_USER_MEM_SUPPORTED
@@ -85,13 +83,13 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
    encounter a png_error() will longjmp here.  Since the jmpbuf is
    then meaningless we abort instead of returning. */
 #ifdef USE_FAR_KEYWORD
-   if (setjmp(png_jmpbuf))
+   if (setjmp(tmp_jmpbuf))
 #else
    if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
 #endif
       PNG_ABORT();
 #ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(png_ptr), png_jmpbuf, png_sizeof(jmp_buf));
+   png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
 #endif
 #endif /* PNG_SETJMP_SUPPORTED */
 
@@ -101,54 +99,9 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
 
    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
 
-   if (user_png_ver)
-   {
-      i = 0;
-
-      do
-      {
-         if (user_png_ver[i] != png_libpng_ver[i])
-            png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
-      } while (png_libpng_ver[i++]);
-   }
-
-   else
-      png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
-
-
-   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
-   {
-     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
-      * we must recompile any applications that use any older library version.
-      * For versions after libpng 1.0, we will be compatible, so we need
-      * only check the first digit.
-      */
-      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
-          (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
-          (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
-      {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-         char msg[80];
-         if (user_png_ver)
-         {
-            png_snprintf2(msg, 80,
-                "Application built with libpng-%.20s"
-                " but running with %.20s",
-                user_png_ver,
-                png_libpng_ver);
-            png_warning(png_ptr, msg);
-         }
-#else
-         png_warning(png_ptr,
-             "Incompatible libpng version in application and library");
-#endif
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-         png_ptr->flags = 0;
-#endif
-
-         png_cleanup_needed = 1;
-      }
-   }
+   /* Call the general version checker (shared with read and write code): */
+   if (!png_user_version_check(png_ptr, user_png_ver))
+      png_cleanup_needed = 1;
 
    if (!png_cleanup_needed)
    {
@@ -457,7 +410,11 @@ png_read_update_info(png_structp png_ptr, png_infop info_ptr)
           "Ignoring extra png_read_update_info() call;"
           " row buffer not reallocated");
 
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
    png_read_transform_info(png_ptr, info_ptr);
+#else
+   PNG_UNUSED(info_ptr)
+#endif
 }
 
 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
@@ -704,8 +661,10 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 #endif
 
 
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
    if (png_ptr->transformations)
       png_do_read_transformations(png_ptr);
+#endif
 
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    /* Blow up interlaced rows to full size */
@@ -1163,7 +1122,9 @@ png_read_destroy(png_structp png_ptr, png_infop info_ptr,
    jmp_buf tmp_jmp;
 #endif
    png_error_ptr error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    png_error_ptr warning_fn;
+#endif
    png_voidp error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
    png_free_ptr free_fn;
@@ -1249,10 +1210,6 @@ png_read_destroy(png_structp png_ptr, png_infop info_ptr,
 #endif
 #endif
 
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-   png_free(png_ptr, png_ptr->time_buffer);
-#endif
-
    inflateEnd(&png_ptr->zstream);
 
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
@@ -1269,11 +1226,13 @@ png_read_destroy(png_structp png_ptr, png_infop info_ptr,
     * being used again.
     */
 #ifdef PNG_SETJMP_SUPPORTED
-   png_memcpy(tmp_jmp, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
+   png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
 #endif
 
    error_fn = png_ptr->error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    warning_fn = png_ptr->warning_fn;
+#endif
    error_ptr = png_ptr->error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
    free_fn = png_ptr->free_fn;
@@ -1282,14 +1241,16 @@ png_read_destroy(png_structp png_ptr, png_infop info_ptr,
    png_memset(png_ptr, 0, png_sizeof(png_struct));
 
    png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    png_ptr->warning_fn = warning_fn;
+#endif
    png_ptr->error_ptr = error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
    png_ptr->free_fn = free_fn;
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
-   png_memcpy(png_ptr->png_jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
+   png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
 #endif
 
 }
@@ -1326,7 +1287,7 @@ png_read_png(png_structp png_ptr, png_infop info_ptr,
    /* -------------- image transformations start here ------------------- */
 
 #ifdef PNG_READ_16_TO_8_SUPPORTED
-   /* Tell libpng to strip 16 bit/color files down to 8 bits per color.
+   /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
     */
    if (transforms & PNG_TRANSFORM_STRIP_16)
       png_set_strip_16(png_ptr);
@@ -1407,7 +1368,7 @@ png_read_png(png_structp png_ptr, png_infop info_ptr,
 #endif
 
 #ifdef PNG_READ_SWAP_SUPPORTED
-   /* Swap bytes of 16 bit files to least significant byte first */
+   /* Swap bytes of 16-bit files to least significant byte first */
    if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
       png_set_swap(png_ptr);
 #endif
@@ -1426,6 +1387,12 @@ png_read_png(png_structp png_ptr, png_infop info_ptr,
       png_set_gray_to_rgb(png_ptr);
 #endif
 
+/* Added at libpng-1.5.3 */
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+   if (transforms & PNG_TRANSFORM_EXPAND_16)
+      png_set_expand_16(png_ptr);
+#endif
+
    /* We don't handle adding filler bytes */
 
    /* We use png_read_image and rely on that for interlace handling, but we also

pngrutil.c

@@ -369,41 +369,31 @@ png_inflate(png_structp png_ptr, png_bytep data, png_size_t size,
        * and the error message is dumped into the uncompressed
        * buffer if available.
        */
+#     ifdef PNG_WARNINGS_SUPPORTED
       {
-         PNG_CONST char *msg;
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-         char umsg[52];
-#endif
+         png_const_charp msg;
+
          if (png_ptr->zstream.msg != 0)
             msg = png_ptr->zstream.msg;
 
-         else
+         else switch (ret)
          {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-            switch (ret)
-            {
-               case Z_BUF_ERROR:
-                  msg = "Buffer error in compressed datastream in %s chunk";
-                  break;
+            case Z_BUF_ERROR:
+               msg = "Buffer error in compressed datastream";
+               break;
 
-               case Z_DATA_ERROR:
-                  msg = "Data error in compressed datastream in %s chunk";
-                  break;
+            case Z_DATA_ERROR:
+               msg = "Data error in compressed datastream";
+               break;
 
-               default:
-                  msg = "Incomplete compressed datastream in %s chunk";
-                  break;
-            }
-
-            png_snprintf(umsg, sizeof umsg, msg, png_ptr->chunk_name);
-            msg = umsg;
-#else
-            msg = "Damaged compressed datastream in chunk other than IDAT";
-#endif
+            default:
+               msg = "Incomplete compressed datastream";
+               break;
          }
 
-         png_warning(png_ptr, msg);
+         png_chunk_warning(png_ptr, msg);
       }
+#     endif
 
       /* 0 means an error - notice that this code simply ignores
        * zero length compressed chunks as a result.
@@ -499,15 +489,9 @@ png_decompress_chunk(png_structp png_ptr, int comp_type,
 
    else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
    {
-#ifdef PNG_STDIO_SUPPORTED
-      char umsg[50];
-
-      png_snprintf(umsg, sizeof umsg,
-          "Unknown zTXt compression type %d", comp_type);
-      png_warning(png_ptr, umsg);
-#else
-      png_warning(png_ptr, "Unknown zTXt compression type");
-#endif
+      PNG_WARNING_PARAMETERS(p)
+      png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, comp_type);
+      png_formatted_warning(png_ptr, p, "Unknown zTXt compression type @1");
 
       /* The recovery is to simply drop the data. */
    }
@@ -845,12 +829,10 @@ png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    {
       if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
       {
-         png_warning(png_ptr,
-             "Ignoring incorrect gAMA value when sRGB is also present");
-
-#    ifdef PNG_CONSOLE_IO_SUPPORTED
-         fprintf(stderr, "gamma = (%d/100000)", (int)igamma);
-#    endif
+         PNG_WARNING_PARAMETERS(p)
+         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, igamma);
+         png_formatted_warning(png_ptr, p,
+             "Ignoring incorrect gAMA value @1 when sRGB is also present");
          return;
       }
    }
@@ -1019,21 +1001,52 @@ png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
           PNG_OUT_OF_RANGE(x_blue,  15000,  1000) ||
           PNG_OUT_OF_RANGE(y_blue,   6000,  1000))
       {
-         png_warning(png_ptr,
-             "Ignoring incorrect cHRM value when sRGB is also present");
+         PNG_WARNING_PARAMETERS(p)
 
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-         fprintf(stderr, "wx=%d, wy=%d, rx=%d, ry=%d\n",
-             x_white, y_white, x_red, y_red);
+         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed, x_white);
+         png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_fixed, y_white);
+         png_warning_parameter_signed(p, 3, PNG_NUMBER_FORMAT_fixed, x_red);
+         png_warning_parameter_signed(p, 4, PNG_NUMBER_FORMAT_fixed, y_red);
+         png_warning_parameter_signed(p, 5, PNG_NUMBER_FORMAT_fixed, x_green);
+         png_warning_parameter_signed(p, 6, PNG_NUMBER_FORMAT_fixed, y_green);
+         png_warning_parameter_signed(p, 7, PNG_NUMBER_FORMAT_fixed, x_blue);
+         png_warning_parameter_signed(p, 8, PNG_NUMBER_FORMAT_fixed, y_blue);
 
-         fprintf(stderr, "gx=%d, gy=%d, bx=%d, by=%d\n",
-             x_green, y_green, x_blue, y_blue);
-#endif /* PNG_CONSOLE_IO_SUPPORTED */
+         png_formatted_warning(png_ptr, p,
+             "Ignoring incorrect cHRM white(@1,@2) r(@3,@4)g(@5,@6)b(@7,@8) "
+             "when sRGB is also present");
       }
       return;
    }
 #endif /* PNG_READ_sRGB_SUPPORTED */
 
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   /* Store the _white values as default coefficients for the rgb to gray
+    * operation if it is supported.
+    */
+   if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+   {
+      /* png_set_background has not been called, the coefficients must be in
+       * range for the following to work without overflow.
+       */
+      if (y_red <= (1<<17) && y_green <= (1<<17) && y_blue <= (1<<17))
+      {
+         /* The y values are chromaticities: Y/X+Y+Z, the weights for the gray
+          * transformation are simply the normalized Y values for red, green and
+          * blue scaled by 32768.
+          */
+         png_uint_32 w = y_red + y_green + y_blue;
+
+         png_ptr->rgb_to_gray_red_coeff   = (png_uint_16)(((png_uint_32)y_red *
+            32768)/w);
+         png_ptr->rgb_to_gray_green_coeff = (png_uint_16)(((png_uint_32)y_green
+            * 32768)/w);
+         png_ptr->rgb_to_gray_blue_coeff  = (png_uint_16)(((png_uint_32)y_blue *
+            32768)/w);
+      }
+   }
+#endif
+
    png_set_cHRM_fixed(png_ptr, info_ptr, x_white, y_white, x_red, y_red,
       x_green, y_green, x_blue, y_blue);
 }
@@ -1095,11 +1108,13 @@ png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    {
       if (PNG_OUT_OF_RANGE(info_ptr->gamma, 45500L, 500))
       {
-         png_warning(png_ptr,
-             "Ignoring incorrect gAMA value when sRGB is also present");
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-         fprintf(stderr, "incorrect gamma=(%d/100000)\n", info_ptr->gamma);
-#endif
+         PNG_WARNING_PARAMETERS(p)
+
+         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_fixed,
+            info_ptr->gamma);
+
+         png_formatted_warning(png_ptr, p,
+             "Ignoring incorrect gAMA value @1 when sRGB is also present");
       }
    }
 #endif /* PNG_READ_gAMA_SUPPORTED */
@@ -1239,23 +1254,15 @@ png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    /* And the following guarantees that profile_size == profile_length. */
    if (profile_size > profile_length)
    {
+      PNG_WARNING_PARAMETERS(p)
+
       png_free(png_ptr, png_ptr->chunkdata);
       png_ptr->chunkdata = NULL;
-#ifdef PNG_STDIO_SUPPORTED
-      {
-         char umsg[80];
 
-         png_snprintf2(umsg, 80,
-             "Ignoring iCCP chunk with declared size = %u "
-              "and actual length = %u",
-              (unsigned int) profile_size,
-              (unsigned int) profile_length);
-         png_warning(png_ptr, umsg);
-      }
-#else
-      png_warning(png_ptr,
-         "Ignoring iCCP chunk with uncompressed size mismatch");
-#endif
+      png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_u, profile_size);
+      png_warning_parameter_unsigned(p, 2, PNG_NUMBER_FORMAT_u, profile_length);
+      png_formatted_warning(png_ptr, p,
+         "Ignoring iCCP chunk with declared size = @1 and actual length = @2");
       return;
    }
 
@@ -1564,6 +1571,7 @@ png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
 {
    png_size_t truelen;
    png_byte buf[6];
+   png_color_16 background;
 
    png_debug(1, "in png_handle_bKGD");
 
@@ -1620,7 +1628,7 @@ png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
     */
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
    {
-      png_ptr->background.index = buf[0];
+      background.index = buf[0];
 
       if (info_ptr && info_ptr->num_palette)
       {
@@ -1630,33 +1638,36 @@ png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
             return;
          }
 
-         png_ptr->background.red =
-             (png_uint_16)png_ptr->palette[buf[0]].red;
-
-         png_ptr->background.green =
-             (png_uint_16)png_ptr->palette[buf[0]].green;
-
-         png_ptr->background.blue =
-             (png_uint_16)png_ptr->palette[buf[0]].blue;
+         background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
+         background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
+         background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
       }
+
+      else
+         background.red = background.green = background.blue = 0;
+
+      background.gray = 0;
    }
 
    else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
    {
-      png_ptr->background.red =
-      png_ptr->background.green =
-      png_ptr->background.blue =
-      png_ptr->background.gray = png_get_uint_16(buf);
+      background.index = 0;
+      background.red =
+      background.green =
+      background.blue =
+      background.gray = png_get_uint_16(buf);
    }
 
    else
    {
-      png_ptr->background.red = png_get_uint_16(buf);
-      png_ptr->background.green = png_get_uint_16(buf + 2);
-      png_ptr->background.blue = png_get_uint_16(buf + 4);
+      background.index = 0;
+      background.red = png_get_uint_16(buf);
+      background.green = png_get_uint_16(buf + 2);
+      background.blue = png_get_uint_16(buf + 4);
+      background.gray = 0;
    }
 
-   png_set_bKGD(png_ptr, info_ptr, &(png_ptr->background));
+   png_set_bKGD(png_ptr, info_ptr, &background);
 }
 #endif
 
@@ -1981,6 +1992,14 @@ png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
       return;
    }
 
+   /* Need unit type, width, \0, height: minimum 4 bytes */
+   else if (length < 4)
+   {
+      png_warning(png_ptr, "sCAL chunk too short");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
    png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
       length + 1);
 
@@ -2016,7 +2035,7 @@ png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    /* Validate the ASCII numbers, need two ASCII numbers separated by
     * a '\0' and they need to fit exactly in the chunk data.
     */
-   i = 0;
+   i = 1;
    state = 0;
 
    if (png_ptr->chunkdata[1] == 45 /* negative width */ ||
@@ -2028,6 +2047,7 @@ png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
    {
       png_size_t heighti = i;
 
+      state = 0;
       if (png_ptr->chunkdata[i] == 45 /* negative height */ ||
           !png_check_fp_number(png_ptr->chunkdata, slength, &state, &i) ||
           i != slength)
@@ -2659,6 +2679,14 @@ png_combine_row(png_structp png_ptr, png_bytep row, int mask)
 {
    png_debug(1, "in png_combine_row");
 
+   /* Added in 1.5.3: the row_info should match the information returned by any
+    * call to png_read_update_info at this point.  Do not continue if we got
+    * this wrong.
+    */
+   if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
+          PNG_ROWBYTES(png_ptr->row_info.pixel_depth, png_ptr->width))
+      png_error(png_ptr, "internal row size calculation error");
+
    if (mask == 0xff)
    {
       png_memcpy(row, png_ptr->row_buf + 1,
@@ -3397,7 +3425,9 @@ png_read_start_row(png_structp png_ptr)
 
    png_debug(1, "in png_read_start_row");
    png_ptr->zstream.avail_in = 0;
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
    png_init_read_transformations(png_ptr);
+#endif
 #ifdef PNG_READ_INTERLACING_SUPPORTED
    if (png_ptr->interlaced)
    {

pngset.c

@@ -94,15 +94,16 @@ png_set_gAMA_fixed(png_structp png_ptr, png_infop info_ptr, png_fixed_point
    if (png_ptr == NULL || info_ptr == NULL)
       return;
 
-   /* Previously these values were limited, however they must be
-    * wrong, therefore storing them (and setting PNG_INFO_gAMA)
-    * must be wrong too.
+   /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
+    * occur.  Since the fixed point representation is assymetrical it is
+    * possible for 1/gamma to overflow the limit of 21474 and this means the
+    * gamma value must be at least 5/100000 and hence at most 20000.0.  For
+    * safety the limits here are a little narrower.  The values are 0.00016 to
+    * 6250.0, which are truely ridiculous gammma values (and will produce
+    * displays that are all black or all white.)
     */
-   if (file_gamma > (png_fixed_point)PNG_UINT_31_MAX)
-      png_warning(png_ptr, "Gamma too large, ignored");
-
-   else if (file_gamma <= 0)
-      png_warning(png_ptr, "Negative or zero gamma ignored");
+   if (file_gamma < 16 || file_gamma > 625000000)
+      png_warning(png_ptr, "Out of range gamma value ignored");
 
    else
    {
@@ -340,11 +341,11 @@ png_set_sCAL_s(png_structp png_ptr, png_infop info_ptr,
    if (unit != 1 && unit != 2)
       png_error(png_ptr, "Invalid sCAL unit");
 
-   if (swidth == NULL || (lengthw = png_strlen(swidth)) <= 0 ||
+   if (swidth == NULL || (lengthw = png_strlen(swidth)) == 0 ||
        swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
       png_error(png_ptr, "Invalid sCAL width");
 
-   if (sheight == NULL || (lengthh = png_strlen(sheight)) <= 0 ||
+   if (sheight == NULL || (lengthh = png_strlen(sheight)) == 0 ||
        sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
       png_error(png_ptr, "Invalid sCAL height");
 
@@ -545,7 +546,7 @@ png_set_sRGB_gAMA_and_cHRM(png_structp png_ptr, png_infop info_ptr,
    png_set_sRGB(png_ptr, info_ptr, srgb_intent);
 
 #  ifdef PNG_gAMA_SUPPORTED
-   png_set_gAMA_fixed(png_ptr, info_ptr, 45455L);
+   png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
 #  endif
 
 #  ifdef PNG_cHRM_SUPPORTED

pngstruct.h

@@ -5,7 +5,7 @@
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  *
- * Last changed in libpng 1.5.0 [January 6, 2011]
+ * Last changed in libpng 1.5.3 [(PENDING RELEASE)]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -29,11 +29,13 @@
 struct png_struct_def
 {
 #ifdef PNG_SETJMP_SUPPORTED
-   jmp_buf png_jmpbuf;            /* used in png_error */
+   jmp_buf longjmp_buffer;    /* used in png_error */
    png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
 #endif
    png_error_ptr error_fn;    /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
    png_error_ptr warning_fn;  /* function for printing warnings */
+#endif
    png_voidp error_ptr;       /* user supplied struct for error functions */
    png_rw_ptr write_data_fn;  /* function for writing output data */
    png_rw_ptr read_data_fn;   /* function for reading input data */
@@ -64,14 +66,29 @@ struct png_struct_def
    z_stream zstream;          /* pointer to decompression structure (below) */
    png_bytep zbuf;            /* buffer for zlib */
    uInt zbuf_size;            /* size of zbuf (typically 65536) */
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Added in 1.5.3: state to keep track of whether the zstream has been
+ * initialized and if so whether it is for IDAT or some other chunk.
+ */
+#define PNG_ZLIB_UNINITIALIZED 0
+#define PNG_ZLIB_FOR_IDAT      1
+#define PNG_ZLIB_FOR_TEXT      2 /* anything other than IDAT */
+#define PNG_ZLIB_USE_MASK      3 /* bottom two bits */
+#define PNG_ZLIB_IN_USE        4 /* a flag value */
+
+   png_uint_32 zlib_state;       /* State of zlib initialization */
+/* End of material added at libpng 1.5.3 */
+
    int zlib_level;            /* holds zlib compression level */
    int zlib_method;           /* holds zlib compression method */
    int zlib_window_bits;      /* holds zlib compression window bits */
    int zlib_mem_level;        /* holds zlib compression memory level */
    int zlib_strategy;         /* holds zlib compression strategy */
+#endif
 /* Added at libpng 1.5.3 */
 #if defined(PNG_WRITE_COMPRESSED_TEXT_SUPPORTED) || \
-    defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION)
+    defined(PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED)
    int zlib_text_level;            /* holds zlib compression level */
    int zlib_text_method;           /* holds zlib compression method */
    int zlib_text_window_bits;      /* holds zlib compression window bits */
@@ -94,6 +111,7 @@ struct png_struct_def
    png_bytep avg_row;         /* buffer to save "avg" row when filtering */
    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
    png_row_info row_info;     /* used for transformation routines */
+   png_size_t info_rowbytes;  /* Added in 1.5.3: cache of updated row bytes */
 
    png_uint_32 idat_size;     /* current IDAT size for read */
    png_uint_32 crc;           /* current chunk CRC value */
@@ -118,7 +136,8 @@ struct png_struct_def
    png_uint_16 filler;           /* filler bytes for pixel expansion */
 #endif
 
-#ifdef PNG_bKGD_SUPPORTED
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+   defined(PNG_READ_ALPHA_MODE_SUPPORTED)
    png_byte background_gamma_type;
    png_fixed_point background_gamma;
    png_color_16 background;   /* background color in screen gamma space */
@@ -219,7 +238,7 @@ struct png_struct_def
 #endif
 
 #ifdef PNG_TIME_RFC1123_SUPPORTED
-   png_charp time_buffer; /* String to hold RFC 1123 time text */
+   char time_buffer[29]; /* String to hold RFC 1123 time text */
 #endif
 
 /* New members added in libpng-1.0.6 */

pngtest.c

@@ -31,6 +31,8 @@
  * of files at once by typing "pngtest -m file1.png file2.png ..."
  */
 
+#define _POSIX_SOURCE 1
+
 #include "zlib.h"
 #include "png.h"
 /* Copied from pngpriv.h but only used in error messages below. */
@@ -779,7 +781,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
    int bit_depth, color_type;
 #ifdef PNG_SETJMP_SUPPORTED
 #ifdef USE_FAR_KEYWORD
-   jmp_buf png_jmpbuf;
+   jmp_buf tmp_jmpbuf;
 #endif
 #endif
 
@@ -848,7 +850,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
 #ifdef PNG_SETJMP_SUPPORTED
    pngtest_debug("Setting jmpbuf for read struct");
 #ifdef USE_FAR_KEYWORD
-   if (setjmp(png_jmpbuf))
+   if (setjmp(tmp_jmpbuf))
 #else
    if (setjmp(png_jmpbuf(read_ptr)))
 #endif
@@ -866,14 +868,14 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
       return (1);
    }
 #ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(read_ptr), png_jmpbuf, png_sizeof(jmp_buf));
+   png_memcpy(png_jmpbuf(read_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
 #endif
 
 #ifdef PNG_WRITE_SUPPORTED
    pngtest_debug("Setting jmpbuf for write struct");
 #ifdef USE_FAR_KEYWORD
 
-   if (setjmp(png_jmpbuf))
+   if (setjmp(tmp_jmpbuf))
 #else
    if (setjmp(png_jmpbuf(write_ptr)))
 #endif
@@ -890,7 +892,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
    }
 
 #ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(write_ptr), png_jmpbuf, png_sizeof(jmp_buf));
+   png_memcpy(png_jmpbuf(write_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
 #endif
 #endif
 #endif
@@ -913,7 +915,7 @@ test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
 #  endif
 #endif
 
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
    /* Normally one would use Z_DEFAULT_STRATEGY for text compression.
     * This is here just to make pngtest replicate the results from libpng
     * versions prior to 1.5.3, and to test this new API.
@@ -1792,4 +1794,4 @@ main(int argc, char *argv[])
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_5_3beta03 Your_png_h_is_not_version_1_5_3beta03;
+typedef png_libpng_version_1_5_4beta01 Your_png_h_is_not_version_1_5_4beta01;

pngtrans.c

@@ -443,8 +443,8 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
     * it is copied to.  ep always points just beyond the end of the row, so
     * the loop simply copies (channels-1) channels until sp reaches ep.
     *
-    * at_start:  0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
-    *         :  nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
+    * at_start:        0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
+    *            nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
     */
 
    /* GA, GX, XG cases */
@@ -454,7 +454,7 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
       {
          if (at_start) /* Skip initial filler */
             ++sp;
-         else          /* Skip initial channels and, for sp, the filler */
+         else          /* Skip initial channel and, for sp, the filler */
             sp += 2, ++dp;
 
          /* For a 1 pixel wide image there is nothing to do */
@@ -466,9 +466,9 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
 
       else if (row_info->bit_depth == 16)
       {
-         if (at_start)
+         if (at_start) /* Skip initial filler */
             sp += 2;
-         else
+         else          /* Skip initial channel and, for sp, the filler */
             sp += 4, dp += 2;
 
          while (sp < ep)
@@ -506,9 +506,9 @@ png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
 
       else if (row_info->bit_depth == 16)
       {
-         if (at_start)
+         if (at_start) /* Skip initial filler */
             sp += 2;
-         else
+         else          /* Skip initial channels and, for sp, the filler */
             sp += 8, dp += 6;
 
          while (sp < ep)

pngwrite.c

@@ -99,8 +99,10 @@ png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
          int keep = png_handle_as_unknown(png_ptr, up->name);
 
          if (keep != PNG_HANDLE_CHUNK_NEVER &&
-             up->location && !(up->location & PNG_HAVE_PLTE) &&
+             up->location &&
+             !(up->location & PNG_HAVE_PLTE) &&
              !(up->location & PNG_HAVE_IDAT) &&
+             !(up->location & PNG_AFTER_IDAT) &&
              ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
              (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
          {
@@ -273,8 +275,10 @@ png_write_info(png_structp png_ptr, png_infop info_ptr)
       {
          int keep = png_handle_as_unknown(png_ptr, up->name);
          if (keep != PNG_HANDLE_CHUNK_NEVER &&
-             up->location && (up->location & PNG_HAVE_PLTE) &&
+             up->location &&
+             (up->location & PNG_HAVE_PLTE) &&
              !(up->location & PNG_HAVE_IDAT) &&
+             !(up->location & PNG_AFTER_IDAT) &&
              ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
              (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
          {
@@ -380,7 +384,8 @@ png_write_end(png_structp png_ptr, png_infop info_ptr)
       {
          int keep = png_handle_as_unknown(png_ptr, up->name);
          if (keep != PNG_HANDLE_CHUNK_NEVER &&
-             up->location && (up->location & PNG_AFTER_IDAT) &&
+             up->location &&
+             (up->location & PNG_AFTER_IDAT) &&
              ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
              (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
          {
@@ -462,10 +467,9 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
    png_structp png_ptr;
 #ifdef PNG_SETJMP_SUPPORTED
 #ifdef USE_FAR_KEYWORD
-   jmp_buf png_jmpbuf;
+   jmp_buf tmp_jmpbuf;
 #endif
 #endif
-   int i;
 
    png_debug(1, "in png_create_write_struct");
 
@@ -489,12 +493,12 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
    encounter a png_error() will longjmp here.  Since the jmpbuf is
    then meaningless we abort instead of returning. */
 #ifdef USE_FAR_KEYWORD
-   if (setjmp(png_jmpbuf))
+   if (setjmp(tmp_jmpbuf))
 #else
    if (setjmp(png_jmpbuf(png_ptr))) /* sets longjmp to match setjmp */
 #endif
 #ifdef USE_FAR_KEYWORD
-   png_memcpy(png_jmpbuf(png_ptr), png_jmpbuf, png_sizeof(jmp_buf));
+   png_memcpy(png_jmpbuf(png_ptr), tmp_jmpbuf, png_sizeof(jmp_buf));
 #endif
       PNG_ABORT();
 #endif
@@ -504,49 +508,8 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
 #endif /* PNG_USER_MEM_SUPPORTED */
    png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
 
-   if (user_png_ver)
-   {
-      i = 0;
-      do
-      {
-         if (user_png_ver[i] != png_libpng_ver[i])
-            png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
-      } while (png_libpng_ver[i++]);
-   }
-
-   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
-   {
-     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
-      * we must recompile any applications that use any older library version.
-      * For versions after libpng 1.0, we will be compatible, so we need
-      * only check the first digit.
-      */
-     if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
-         (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
-         (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
-     {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-        char msg[80];
-
-        if (user_png_ver)
-        {
-            png_snprintf2(msg, 80,
-                "Application built with libpng-%.20s"
-                " but running with %.20s",
-                user_png_ver,
-                png_libpng_ver);
-            png_warning(png_ptr, msg);
-         }
-#else
-         png_warning(png_ptr,
-             "Incompatible libpng version in application and library");
-#endif
-#ifdef PNG_ERROR_NUMBERS_SUPPORTED
-        png_ptr->flags = 0;
-#endif
-        png_cleanup_needed = 1;
-     }
-   }
+   if (!png_user_version_check(png_ptr, user_png_ver))
+      png_cleanup_needed = 1;
 
    /* Initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
@@ -805,9 +768,11 @@ png_write_row(png_structp png_ptr, png_const_bytep row)
    }
 #endif
 
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
    /* Handle other transformations */
    if (png_ptr->transformations)
       png_do_write_transformations(png_ptr);
+#endif
 
 #ifdef PNG_MNG_FEATURES_SUPPORTED
    /* Write filter_method 64 (intrapixel differencing) only if
@@ -884,8 +849,6 @@ png_write_flush(png_structp png_ptr)
       {
          /* Write the IDAT and reset the zlib output buffer */
          png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-         png_ptr->zstream.next_out = png_ptr->zbuf;
-         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
          wrote_IDAT = 1;
       }
    } while (wrote_IDAT == 1);
@@ -896,8 +859,6 @@ png_write_flush(png_structp png_ptr)
       /* Write the IDAT and reset the zlib output buffer */
       png_write_IDAT(png_ptr, png_ptr->zbuf,
           png_ptr->zbuf_size - png_ptr->zstream.avail_out);
-      png_ptr->zstream.next_out = png_ptr->zbuf;
-      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
    }
    png_ptr->flush_rows = 0;
    png_flush(png_ptr);
@@ -983,7 +944,9 @@ png_write_destroy(png_structp png_ptr)
    jmp_buf tmp_jmp; /* Save jump buffer */
 #endif
    png_error_ptr error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    png_error_ptr warning_fn;
+#endif
    png_voidp error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
    png_free_ptr free_fn;
@@ -992,7 +955,8 @@ png_write_destroy(png_structp png_ptr)
    png_debug(1, "in png_write_destroy");
 
    /* Free any memory zlib uses */
-   deflateEnd(&png_ptr->zstream);
+   if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
+      deflateEnd(&png_ptr->zstream);
 
    /* Free our memory.  png_free checks NULL for us. */
    png_free(png_ptr, png_ptr->zbuf);
@@ -1005,10 +969,6 @@ png_write_destroy(png_structp png_ptr)
    png_free(png_ptr, png_ptr->paeth_row);
 #endif
 
-#ifdef PNG_TIME_RFC1123_SUPPORTED
-   png_free(png_ptr, png_ptr->time_buffer);
-#endif
-
 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
    /* Use this to save a little code space, it doesn't free the filter_costs */
    png_reset_filter_heuristics(png_ptr);
@@ -1018,11 +978,13 @@ png_write_destroy(png_structp png_ptr)
 
 #ifdef PNG_SETJMP_SUPPORTED
    /* Reset structure */
-   png_memcpy(tmp_jmp, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
+   png_memcpy(tmp_jmp, png_ptr->longjmp_buffer, png_sizeof(jmp_buf));
 #endif
 
    error_fn = png_ptr->error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    warning_fn = png_ptr->warning_fn;
+#endif
    error_ptr = png_ptr->error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
    free_fn = png_ptr->free_fn;
@@ -1031,14 +993,16 @@ png_write_destroy(png_structp png_ptr)
    png_memset(png_ptr, 0, png_sizeof(png_struct));
 
    png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
    png_ptr->warning_fn = warning_fn;
+#endif
    png_ptr->error_ptr = error_ptr;
 #ifdef PNG_USER_MEM_SUPPORTED
    png_ptr->free_fn = free_fn;
 #endif
 
 #ifdef PNG_SETJMP_SUPPORTED
-   png_memcpy(png_ptr->png_jmpbuf, tmp_jmp, png_sizeof(jmp_buf));
+   png_memcpy(png_ptr->longjmp_buffer, tmp_jmp, png_sizeof(jmp_buf));
 #endif
 }
 
@@ -1451,6 +1415,9 @@ png_set_compression_strategy(png_structp png_ptr, int strategy)
    png_ptr->zlib_strategy = strategy;
 }
 
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
 void PNGAPI
 png_set_compression_window_bits(png_structp png_ptr, int window_bits)
 {
@@ -1492,7 +1459,7 @@ png_set_compression_method(png_structp png_ptr, int method)
 }
 
 /* The following were added to libpng-1.5.3 */
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 void PNGAPI
 png_set_text_compression_level(png_structp png_ptr, int level)
 {
@@ -1529,6 +1496,9 @@ png_set_text_compression_strategy(png_structp png_ptr, int strategy)
    png_ptr->zlib_text_strategy = strategy;
 }
 
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
 void PNGAPI
 png_set_text_compression_window_bits(png_structp png_ptr, int window_bits)
 {
@@ -1568,7 +1538,7 @@ png_set_text_compression_method(png_structp png_ptr, int method)
    png_ptr->flags |= PNG_FLAG_ZTXT_CUSTOM_METHOD;
    png_ptr->zlib_text_method = method;
 }
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
 /* end of API added to libpng-1.5.3 */
 
 void PNGAPI
@@ -1637,7 +1607,7 @@ png_write_png(png_structp png_ptr, png_infop info_ptr,
 #endif
 
 #ifdef PNG_WRITE_FILLER_SUPPORTED
-   /* Pack XRGB/RGBX/ARGB/RGBA into * RGB (4 channels -> 3 channels) */
+   /* Pack XRGB/RGBX/ARGB/RGBA into RGB (4 channels -> 3 channels) */
    if (transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER)
       png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
 

pngwtran.c

@@ -15,6 +15,7 @@
 
 #ifdef PNG_WRITE_SUPPORTED
 
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
 /* Transform the data according to the user's wishes.  The order of
  * transformations is significant.
  */
@@ -563,6 +564,7 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
    }
 }
 #endif
+#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
 
 #ifdef PNG_MNG_FEATURES_SUPPORTED
 /* Undoes intrapixel differencing  */

pngwutil.c

@@ -192,6 +192,148 @@ png_write_chunk_end(png_structp png_ptr)
    png_write_data(png_ptr, buf, (png_size_t)4);
 }
 
+/* Initialize the compressor for the appropriate type of compression. */
+static void
+png_zlib_claim(png_structp png_ptr, png_uint_32 state)
+{
+   if (!(png_ptr->zlib_state & PNG_ZLIB_IN_USE))
+   {
+      /* If already initialized for 'state' do not re-init. */
+      if (png_ptr->zlib_state != state)
+      {
+         int ret = Z_OK;
+         png_const_charp who = "-";
+
+         /* If actually initialized for another state do a deflateEnd. */
+         if (png_ptr->zlib_state != PNG_ZLIB_UNINITIALIZED)
+         {
+            ret = deflateEnd(&png_ptr->zstream);
+            who = "end";
+            png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
+         }
+
+         /* zlib itself detects an incomplete state on deflateEnd */
+         if (ret == Z_OK) switch (state)
+         {
+#           ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+               case PNG_ZLIB_FOR_TEXT:
+                  ret = deflateInit2(&png_ptr->zstream,
+                     png_ptr->zlib_text_level, png_ptr->zlib_text_method,
+                     png_ptr->zlib_text_window_bits,
+                     png_ptr->zlib_text_mem_level, png_ptr->zlib_text_strategy);
+                  who = "text";
+                  break;
+#           endif
+
+            case PNG_ZLIB_FOR_IDAT:
+               ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
+                   png_ptr->zlib_method, png_ptr->zlib_window_bits,
+                   png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
+               who = "IDAT";
+               break;
+
+            default:
+               png_error(png_ptr, "invalid zlib state");
+         }
+
+         if (ret == Z_OK)
+            png_ptr->zlib_state = state;
+
+         else /* an error in deflateEnd or deflateInit2 */
+         {
+            size_t pos = 0;
+            char msg[64];
+
+            pos = png_safecat(msg, sizeof msg, pos,
+               "zlib failed to initialize compressor (");
+            pos = png_safecat(msg, sizeof msg, pos, who);
+
+            switch (ret)
+            {
+               case Z_VERSION_ERROR:
+                  pos = png_safecat(msg, sizeof msg, pos, ") version error");
+                  break;
+
+               case Z_STREAM_ERROR:
+                  pos = png_safecat(msg, sizeof msg, pos, ") stream error");
+                  break;
+
+               case Z_MEM_ERROR:
+                  pos = png_safecat(msg, sizeof msg, pos, ") memory error");
+                  break;
+
+               default:
+                  pos = png_safecat(msg, sizeof msg, pos, ") unknown error");
+                  break;
+            }
+
+            png_error(png_ptr, msg);
+         }
+      }
+
+      /* Here on success, claim the zstream: */
+      png_ptr->zlib_state |= PNG_ZLIB_IN_USE;
+   }
+
+   else
+      png_error(png_ptr, "zstream already in use (internal error)");
+}
+
+/* The opposite: release the stream.  It is also reset, this API will warn on
+ * error but will not fail.
+ */
+static void
+png_zlib_release(png_structp png_ptr)
+{
+   if (png_ptr->zlib_state & PNG_ZLIB_IN_USE)
+   {
+      int ret = deflateReset(&png_ptr->zstream);
+
+      png_ptr->zlib_state &= ~PNG_ZLIB_IN_USE;
+
+      if (ret != Z_OK)
+      {
+         png_const_charp err;
+         PNG_WARNING_PARAMETERS(p)
+
+         switch (ret)
+         {
+            case Z_VERSION_ERROR:
+               err = "version";
+               break;
+
+            case Z_STREAM_ERROR:
+               err = "stream";
+               break;
+
+            case Z_MEM_ERROR:
+               err = "memory";
+               break;
+
+            default:
+               err = "unknown";
+               break;
+         }
+
+         png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, ret);
+         png_warning_parameter(p, 2, err);
+
+         if (png_ptr->zstream.msg)
+            err = png_ptr->zstream.msg;
+         else
+            err = "[no zlib message]";
+
+         png_warning_parameter(p, 3, err);
+
+         png_formatted_warning(png_ptr, p,
+            "zlib failed to reset compressor: @1(@2): @3");
+      }
+   }
+
+   else
+      png_warning(png_ptr, "zstream not in use (internal error)");
+}
+
 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
 /* This pair of functions encapsulates the operation of (a) compressing a
  * text string, and (b) issuing it later as a series of chunk data writes.
@@ -231,13 +373,11 @@ png_text_compress(png_structp png_ptr,
 
    if (compression >= PNG_TEXT_COMPRESSION_LAST)
    {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-      char msg[50];
-      png_snprintf(msg, 50, "Unknown compression type %d", compression);
-      png_warning(png_ptr, msg);
-#else
-      png_warning(png_ptr, "Unknown compression type");
-#endif
+      PNG_WARNING_PARAMETERS(p)
+
+      png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d,
+         compression);
+      png_formatted_warning(png_ptr, p, "Unknown compression type @1");
    }
 
    /* We can't write the chunk until we find out how much data we have,
@@ -254,37 +394,7 @@ png_text_compress(png_structp png_ptr,
     * data, or if the input string is incredibly large (although this
     * wouldn't cause a failure, just a slowdown due to swapping).
     */
-
-   if (!(png_ptr->mode & PNG_ZLIB_READY_FOR_ZTXT))
-     {
-
-        /* png_warning(png_ptr, "Initialize compressor for ztxt"); */
-        /* Free memory from previously opened zstream */
-        deflateEnd(&png_ptr->zstream);
-
-        /* Initialize the compressor for zTXt compression. */
-        ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_text_level,
-            png_ptr->zlib_text_method, png_ptr->zlib_text_window_bits,
-            png_ptr->zlib_text_mem_level, png_ptr->zlib_text_strategy);
-
-        if (ret != Z_OK)
-        {
-           if (ret == Z_VERSION_ERROR)
-              png_error(png_ptr,
-              "zlib failed to initialize compressor for text-- version error");
-
-           if (ret == Z_STREAM_ERROR)
-              png_error(png_ptr,
-             "zlib failed to initialize compressor for text-- stream error");
-
-           if (ret == Z_MEM_ERROR)
-              png_error(png_ptr,
-             "zlib failed to initialize compressor for text-- mem error");
-
-           png_error(png_ptr, "zlib failed to initialize compressor for text");
-      }
-      png_ptr->mode |= PNG_ZLIB_READY_FOR_ZTXT;
-   }
+   png_zlib_claim(png_ptr, PNG_ZLIB_FOR_TEXT);
 
    /* Set up the compression buffers */
    /* TODO: the following cast hides a potential overflow problem. */
@@ -449,6 +559,7 @@ png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
       return;
    }
 
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
    if (comp->input_len >= 2 && comp->input_len < 16384)
    {
       unsigned int z_cmf;  /* zlib compression method and flags */
@@ -466,12 +577,12 @@ png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
       {
          unsigned int z_cinfo;
          unsigned int half_z_window_size;
-         png_size_t uncompressed_idat_size = comp->input_len;
+         png_size_t uncompressed_text_size = comp->input_len;
 
          z_cinfo = z_cmf >> 4;
          half_z_window_size = 1 << (z_cinfo + 7);
 
-         while (uncompressed_idat_size <= half_z_window_size &&
+         while (uncompressed_text_size <= half_z_window_size &&
              half_z_window_size >= 256)
          {
             z_cinfo--;
@@ -508,6 +619,7 @@ png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
          png_error(png_ptr,
              "Invalid zlib compression method or flags in non-IDAT chunk");
    }
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
 
    /* Write saved output buffers, if any */
    for (i = 0; i < comp->num_output_ptr; i++)
@@ -527,7 +639,7 @@ png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
           (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
 
    /* Reset zlib for another zTXt/iTXt or image data */
-   deflateReset(&png_ptr->zstream);
+   png_zlib_release(png_ptr);
 }
 #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
 
@@ -541,7 +653,6 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
     int interlace_type)
 {
    PNG_IHDR;
-   int ret;
 
    png_byte buf[13]; /* Buffer to store the IHDR info */
 
@@ -723,7 +834,7 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
       png_ptr->zlib_method = 8;
 
 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
    if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_STRATEGY))
       png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
 
@@ -744,13 +855,11 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
    png_ptr->zlib_text_mem_level = png_ptr->zlib_mem_level;
    png_ptr->zlib_text_window_bits = png_ptr->zlib_window_bits;
    png_ptr->zlib_text_method = png_ptr->zlib_method;
-#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED */
 #endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
 
-   /* Initialize the zlib compressor */
-   ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
-       png_ptr->zlib_method, png_ptr->zlib_window_bits,
-       png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
+   /* Record that the compressor has not yet been initialized. */
+   png_ptr->zlib_state = PNG_ZLIB_UNINITIALIZED;
 
    png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
 }
@@ -837,55 +946,14 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
 
    png_debug(1, "in png_write_IDAT");
 
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
    if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
        png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
    {
-      unsigned int z_cmf;  /* zlib compression method and flags */
-
-#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
-      int ret;
-
-      /* Reinitialize the compressor if necessary */
-      if (png_ptr->mode & PNG_ZLIB_READY_FOR_ZTXT)
-      {
-         /* Free memory from previously opened zstream */
-         deflateEnd(&png_ptr->zstream);
-
-         ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
-             png_ptr->zlib_method, png_ptr->zlib_window_bits,
-             png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
-
-         if (ret != Z_OK)
-         {
-            if (ret == Z_VERSION_ERROR)
-               png_error(png_ptr,
-                  "zlib failed to initialize compressor -- version error");
-
-            if (ret == Z_STREAM_ERROR)
-               png_error(png_ptr,
-                   "zlib failed to initialize compressor -- stream error");
-
-            if (ret == Z_MEM_ERROR)
-               png_error(png_ptr,
-                   "zlib failed to initialize compressor -- mem error");
-
-            png_error(png_ptr, "zlib failed to initialize compressor");
-         }
-         png_ptr->mode &= ~PNG_ZLIB_READY_FOR_ZTXT; /* Ready for IDAT */
-      }
-#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
-
-      png_ptr->zstream.next_out = png_ptr->zbuf;
-      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
-      /* libpng is not interested in zstream.data_type, so set it
-       * to a predefined value, to avoid its evaluation inside zlib
-       */
-      png_ptr->zstream.data_type = Z_BINARY;
-
       /* Optimize the CMF field in the zlib stream.  This hack of the zlib
        * stream is compliant to the stream specification.
        */
-      z_cmf = data[0];
+      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
 
       if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
       {
@@ -899,7 +967,7 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
          {
             /* Compute the maximum possible length of the datastream */
 
-            /* Number of pixels, plus for each row a filter byte and possible
+            /* Number of pixels, plus for each row a filter byte
              * and possibly a padding byte, so increase the maximum
              * size to account for these.
              */
@@ -944,9 +1012,17 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
          png_error(png_ptr,
              "Invalid zlib compression method or flags in IDAT");
    }
+#endif /* PNG_WRITE_OPTIMIZE_CMF_SUPPORTED */
 
    png_write_chunk(png_ptr, png_IDAT, data, length);
    png_ptr->mode |= PNG_HAVE_IDAT;
+
+   /* Prior to 1.5.3 this code was replicated in every caller (except at the
+    * end, where it isn't technically necessary).  Since this function has
+    * flushed the data we can safely reset the zlib output buffer here.
+    */
+   png_ptr->zstream.next_out = png_ptr->zbuf;
+   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
 }
 
 /* Write an IEND chunk */
@@ -1470,15 +1546,11 @@ png_check_keyword(png_structp png_ptr, png_const_charp key, png_charpp new_key)
       if ((png_byte)*ikp < 0x20 ||
          ((png_byte)*ikp > 0x7E && (png_byte)*ikp < 0xA1))
       {
-#ifdef PNG_CONSOLE_IO_SUPPORTED
-         char msg[40];
+         PNG_WARNING_PARAMETERS(p)
 
-         png_snprintf(msg, 40,
-             "invalid keyword character 0x%02X", (png_byte)*ikp);
-         png_warning(png_ptr, msg);
-#else
-         png_warning(png_ptr, "invalid character in keyword");
-#endif
+         png_warning_parameter_unsigned(p, 1, PNG_NUMBER_FORMAT_02x,
+            (png_byte)*ikp);
+         png_formatted_warning(png_ptr, p, "invalid keyword character 0x@1");
          *dp = ' ';
       }
 
@@ -2029,6 +2101,7 @@ png_write_start_row(png_structp png_ptr)
       png_ptr->usr_width = png_ptr->width;
    }
 
+   png_zlib_claim(png_ptr, PNG_ZLIB_FOR_IDAT);
    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
    png_ptr->zstream.next_out = png_ptr->zbuf;
 }
@@ -2150,7 +2223,7 @@ png_write_finish_row(png_structp png_ptr)
           png_ptr->zstream.avail_out);
    }
 
-   deflateReset(&png_ptr->zstream);
+   png_zlib_release(png_ptr);
    png_ptr->zstream.data_type = Z_BINARY;
 }
 
@@ -2339,6 +2412,8 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
  * been specified by the application, and then writes the row out with the
  * chosen filter.
  */
+static void png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row);
+
 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
 #define PNG_HISHIFT 10
 #define PNG_LOMASK ((png_uint_32)0xffffL)
@@ -3014,7 +3089,7 @@ png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
 
 
 /* Do the actual writing of a previously filtered row. */
-void /* PRIVATE */
+static void
 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
 {
    png_size_t avail;
@@ -3074,8 +3149,6 @@ png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
       {
          /* Write the IDAT and reset the zlib output buffer */
          png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-         png_ptr->zstream.next_out = png_ptr->zbuf;
-         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
       }
    /* Repeat until all data has been compressed */
    } while (avail > 0 || png_ptr->zstream.avail_in > 0);

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+set zlib=..\..\..\zlib
+set awk=
+#
+@if not exist pngconfig.dfa $(MAKE) $(__MAKEOPTS__) -f pngconfig.mak defaults
+@if exist config.inf type config.inf
+@echo Checking for the libpng configuration file pnglibconf.h
+$(MAKE) $(__MAKEOPTS__) -f pngconfig.mak
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+3
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projects/owatcom/pngconfig.mak

@@ -0,0 +1,160 @@
+# This is an OpenWatcom make file which builds pnglibconf.h - the libpng
+# configuration header.  You can ignore this file if you don't need to
+# configure libpng; a default configuration will be built.
+#
+# For more information build libpng.wpj under the IDE and then read the
+# generated files:
+#
+#    config.inf: Basic configuration information for a standard build.
+#    pngconfig.dfa: Advanced configuration for non-standard libpng builds.
+#
+DELETE=rm -f
+ECHO=echo
+COPY=copy
+#
+# If your configuration needs to test compiler flags when building
+# pnglibconf.h you may need to override the following on the wmake command
+# line:
+CFLAGS=
+CC=wcl386
+CPP=$(CC) -pw0
+#
+# Read awk from the environment if set, else it can be set on the command
+# line (the default approach is to set the %awk% environment variable in the
+# IDE libpng.wpj 'before' rule - this setting is local.)
+!ifdef %awk
+AWK=$(%awk)
+!endif
+#
+# pnglibconf.h must exist in the source directory, this is the final rule
+# which copies the local built version (and this is the default target for
+# this makefile.)
+..\..\pnglibconf.h: pnglibconf.h
+ $(COPY) pnglibconf.h $@
+
+!ifdef AWK
+# CPPFLAGS should contain the options to control the result,
+# but DEFS and CFLAGS are also supported here, override
+# as appropriate
+DFNFLAGS = $(DEFS) $(CPPFLAGS) $(CFLAGS)
+
+pnglibconf.h: pnglibconf.dfn
+ $(DELETE) $@ dfn.c dfn1.out dfn2.out
+ $(ECHO) $#include "pnglibconf.dfn" >dfn.c
+ $(CPP) $(DFNFLAGS) dfn.c >dfn1.out
+ $(AWK) -f << dfn1.out >dfn2.out
+/^.*PNG_DEFN_MAGIC-.*-PNG_DEFN_END.*$$/{
+ sub(/^.*PNG_DEFN_MAGIC-/, "")
+ sub(/ *-PNG_DEFN_END.*$$/, "")
+ gsub(/ *@@@ */, "")
+ print
+}
+<<
+ $(COPY) dfn2.out $@
+ @type << >pngconfig.inf
+This is a locally configurable build of libpng.lib; for configuration
+instructions consult and edit projects/openwatcom/pngconfig.dfa
+<<
+ $(DELETE) dfn.c dfn1.out dfn2.out
+
+pnglibconf.dfn: ..\..\scripts\pnglibconf.dfa ..\..\scripts\options.awk pngconfig.dfa
+ $(DELETE) $@ dfn1.out dfn2.out
+ $(AWK) -f ..\..\scripts\options.awk out=dfn1.out ..\..\scripts\pnglibconf.dfa pngconfig.dfa $(DFA_XTRA) 1>&2
+ $(AWK) -f ..\..\scripts\options.awk out=dfn2.out dfn1.out 1>&2
+ $(COPY) dfn2.out $@
+ $(DELETE) dfn1.out dfn2.out
+
+!else
+# The following lines are used to copy scripts\pnglibconf.h.prebuilt and make
+# the required change to the calling convention.
+#
+# By default libpng is built to use the __cdecl calling convention on
+# Windows.  This gives compatibility with MSVC and GCC.  Unfortunately it
+# does not work with OpenWatcom because OpenWatcom implements longjmp using
+# the __watcall convention (compared with both MSVC and GCC which use __cdecl
+# for library functions.)
+#
+# Thus the default must be changed to build on OpenWatcom and, once changed,
+# the result will not be compatible with applications built using other
+# compilers (in fact attempts to build will fail at compile time.)
+#
+pnglibconf.h: ..\..\scripts\pnglibconf.h.prebuilt .existsonly
+ @$(ECHO) .
+ @$(ECHO) .
+ @$(ECHO) $$(AWK) NOT AVAILABLE: COPYING scripts\pnglibconf.h.prebuilt
+ @$(ECHO) .
+ @$(ECHO) .
+ vi -q -k ":1,$$s/PNG_API_RULE 0$$/PNG_API_RULE 2/\n:w! $@\n:q!\n" ..\..\scripts\pnglibconf.h.prebuilt
+ @$(ECHO) .
+ @$(ECHO) .
+ @$(ECHO) YOU HAVE A DEFAULT CONFIGURATION BECAUSE YOU DO NOT HAVE AWK!
+ @$(ECHO) .
+ @$(ECHO) .
+ @type << >pngconfig.inf
+This is the default configuration of libpng.lib, if you wish to
+change the configuration please consult the instructions in
+projects/owatcom/pngconfig.dfa.
+<<
+
+!endif
+
+# Make the default files
+defaults: .symbolic
+ @$(COPY) << config.inf
+$# The libpng project is incompletely configured.  To complete configuration
+$# please complete the following steps:
+$#
+$#   1) Edit the 'before' rule of libpng.wpj (from the IDE) to define the
+$#      locations of the zlib include file zlib.h and the built zlib library,
+$#      zlib.lib.
+$#
+$#   2) If you want to change libpng to a non-standard configuration also
+$#      change the definition of 'awk' in the before rule to the name of your
+$#      awk command.  For more instructions on configuration read
+$#      pngconfig.dfa.
+$#
+$#   3) Delete this file (config.inf).
+<<
+ @$(COPY) << pngconfig.dfa
+$# pngconfig.dfa: this file contains configuration options for libpng.
+$# If emtpy the standard configuration will be built.  For this file to be
+$# used a working version of the program 'awk' is required and the program
+$# must be identified in the 'before' rule of the project.
+$#
+$# If you don't already have 'awk', or the version of awk you have seems not
+$# to work, download Brian Kernighan's awk (Brian Kernighan is the author of
+$# awk.)  You can find source code and a built executable (called awk95.exe)
+$# here:
+$#
+$#     http://www.cs.princeton.edu/~bwk/btl.mirror/
+$#
+$# The executable works just fine.
+$#
+$# If build issues errors after a change to pngconfig.dfa you have entered
+$# inconsistent feature requests, or even malformed requests, in
+$# pngconfig.dfa.  The error messages from awk should be comprehensible, but
+$# if not simply go back to the start (nothing but comments in this file) and
+$# enter configuration lines one by one until one produces an error.  (Or, of
+$# course, do the standard binary chop.)
+$#
+$# You need to rebuild everything after a change to pnglibconf.dfa - i.e. you
+$# must do Actions/Mark All Targets for Remake.  This is because the compiler
+$# generated dependency information (as of OpenWatcom 1.9) does not record the
+$# dependency on pnglibconf.h correctly.
+$#
+$# If awk isn't set then this file is bypassed.  If you just want the standard
+$# configuration it is automatically produced from the distributed version
+$# (scripts\pnglibconf.h.prebuilt) by editting PNG_API_RULE to 2 (to force use
+$# of the OpenWatcom library calling convention.)
+$#
+<<
+
+clean:: .symbolic
+ $(DELETE) ..\..\pnglibconf.h pnglibconf.* dfn.c *.out pngconfig.inf
+ $(DELETE) *.obj *.mbr *.sym *.err *.pch libpng.mk
+ $(DELETE) libpng.lib libpng.lbr libpng.lb1 libpng.cbr libpng.mk1
+ $(DELETE) pngtest.exe pngtest.map pngtest.lk1 pngtest.mk1
+ $(DELETE) pngvalid.exe pngvalid.map pngvalid.lk1 pngvalid.mk1
+
+distclean:: clean .symbolic
+ $(DELETE) zlib.inf awk.inf config.inf pngconfig.dfa

projects/owatcom/pngtest.tgt

@@ -0,0 +1,179 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+34
+cd ..\..
+projects\owatcom\pngtest
+6
+MItem
+11
+pngtest.exe
+7
+WString
+4
+NEXE
+8
+WVList
+4
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+28
+?????Library directories(;):
+1
+12
+WString
+8
+$(%zlib)
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+18
+?????Libraries(,):
+1
+16
+WString
+19
+libpng.lib zlib.lib
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+28
+?????Library directories(;):
+0
+20
+WString
+8
+$(%zlib)
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+18
+?????Libraries(,):
+0
+24
+WString
+19
+libpng.lib zlib.lib
+0
+25
+WVList
+0
+-1
+1
+1
+0
+26
+WPickList
+2
+27
+MItem
+3
+*.c
+28
+WString
+4
+COBJ
+29
+WVList
+2
+30
+MVState
+31
+WString
+3
+WCC
+32
+WString
+25
+n????Include directories:
+1
+33
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+34
+MVState
+35
+WString
+3
+WCC
+36
+WString
+25
+n????Include directories:
+0
+37
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+38
+WVList
+0
+-1
+1
+1
+0
+39
+MItem
+15
+..\..\pngtest.c
+40
+WString
+4
+COBJ
+41
+WVList
+0
+42
+WVList
+0
+27
+1
+1
+0

projects/owatcom/pngvalid.tgt

@@ -0,0 +1,210 @@
+40
+targetIdent
+0
+MProject
+1
+MComponent
+0
+2
+WString
+4
+NEXE
+3
+WString
+5
+nc2en
+1
+0
+0
+4
+MCommand
+0
+5
+MCommand
+8
+pngvalid
+6
+MItem
+12
+pngvalid.exe
+7
+WString
+4
+NEXE
+8
+WVList
+6
+9
+MVState
+10
+WString
+7
+WINLINK
+11
+WString
+11
+?????Stack:
+1
+12
+WString
+4
+768k
+0
+13
+MVState
+14
+WString
+7
+WINLINK
+15
+WString
+28
+?????Library directories(;):
+1
+16
+WString
+8
+$(%zlib)
+0
+17
+MVState
+18
+WString
+7
+WINLINK
+19
+WString
+18
+?????Libraries(,):
+1
+20
+WString
+19
+libpng.lib zlib.lib
+0
+21
+MVState
+22
+WString
+7
+WINLINK
+23
+WString
+11
+?????Stack:
+0
+24
+WString
+4
+768k
+0
+25
+MVState
+26
+WString
+7
+WINLINK
+27
+WString
+28
+?????Library directories(;):
+0
+28
+WString
+8
+$(%zlib)
+0
+29
+MVState
+30
+WString
+7
+WINLINK
+31
+WString
+18
+?????Libraries(,):
+0
+32
+WString
+19
+libpng.lib zlib.lib
+0
+33
+WVList
+0
+-1
+1
+1
+0
+34
+WPickList
+2
+35
+MItem
+3
+*.c
+36
+WString
+4
+COBJ
+37
+WVList
+2
+38
+MVState
+39
+WString
+3
+WCC
+40
+WString
+25
+n????Include directories:
+1
+41
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+42
+MVState
+43
+WString
+3
+WCC
+44
+WString
+25
+n????Include directories:
+0
+45
+WString
+39
+"$(%zlib);$(%watcom)/h;$(%watcom)/h/nt"
+0
+46
+WVList
+0
+-1
+1
+1
+0
+47
+MItem
+16
+..\..\pngvalid.c
+48
+WString
+4
+COBJ
+49
+WVList
+0
+50
+WVList
+0
+35
+1
+1
+0

projects/visualc71/PRJ0041.mak

@@ -9,7 +9,7 @@ all: $(IntDir)\alloc.h \
 	 $(IntDir)\strings.h \
 	 $(IntDir)\unistd.h \
 	 $(IntDir)\unixio.h
-	 
+
 $(IntDir)\alloc.h \
 $(IntDir)\fp.h \
 $(IntDir)\m68881.h \

projects/vstudio/readme.txt

@@ -1,7 +1,7 @@
 
 VisualStudio instructions
 
-libpng version 1.5.3beta03 - April 17, 2011
+libpng version 1.5.4beta01 - June 14, 2011
 
 Copyright (c) 1998-2010 Glenn Randers-Pehrson
 

projects/vstudio/zlib.props

@@ -2,7 +2,7 @@
 <!--
  * zlib.props - location of zlib source
  *
- * libpng version 1.5.3beta03 - April 17, 2011
+ * libpng version 1.5.4beta01 - June 14, 2011
  *
  * Copyright (c) 1998-2011 Glenn Randers-Pehrson
  *

scripts/README.txt

@@ -1,9 +1,9 @@
 
-Makefiles for  libpng version 1.5.3beta03 - April 17, 2011
+Makefiles for  libpng version 1.5.4beta01 - June 14, 2011
 
 pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.linux    =>  Linux/ELF makefile
-                       (gcc, creates libpng15.so.15.1.5.3beta03)
+                       (gcc, creates libpng15.so.15.1.5.4beta01)
  makefile.gcc      =>  Generic makefile (gcc, creates static libpng.a)
  makefile.knr      =>  Archaic UNIX Makefile that converts files with
                        ansi2knr (Requires ansi2knr.c from
@@ -20,7 +20,7 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.dec      =>  DEC Alpha UNIX makefile
  makefile.dj2      =>  DJGPP 2 makefile
  makefile.elf      =>  Linux/ELF makefile symbol versioning,
-                       (gcc, creates libpng15.so.15.1.5.3beta03)
+                       (gcc, creates libpng15.so.15.1.5.4beta01)
  makefile.freebsd  =>  FreeBSD makefile
  makefile.gcc      =>  Generic gcc makefile
  makefile.hpgcc    =>  HPUX makefile using gcc
@@ -35,19 +35,18 @@ pnglibconf.h.prebuilt       =>  Stores configuration settings
  makefile.os2      =>  OS/2 Makefile (gcc and emx, requires libpng.def)
  makefile.sco      =>  For SCO OSr5  ELF and Unixware 7 with Native cc
  makefile.sggcc    =>  Silicon Graphics (gcc,
-                       creates libpng15.so.15.1.5.3beta03)
+                       creates libpng15.so.15.1.5.4beta01)
  makefile.sgi      =>  Silicon Graphics IRIX makefile (cc, creates static lib)
  makefile.solaris  =>  Solaris 2.X makefile (gcc,
-                       creates libpng15.so.15.1.5.3beta03)
+                       creates libpng15.so.15.1.5.4beta01)
  makefile.so9      =>  Solaris 9 makefile (gcc,
-                       creates libpng15.so.15.1.5.3beta03)
+                       creates libpng15.so.15.1.5.4beta01)
  makefile.std      =>  Generic UNIX makefile (cc, creates static libpng.a)
  makefile.sunos    =>  Sun makefile
  makefile.32sunu   =>  Sun Ultra 32-bit makefile
  makefile.64sunu   =>  Sun Ultra 64-bit makefile
  makefile.tc3      =>  Turbo C 3.0 makefile
  makefile.vcwin32  =>  makefile for Microsoft Visual C++ 4.0 and later
- makefile.watcom   =>  Watcom 10a+ Makefile, 32-bit flat memory model
  makevms.com       =>  VMS build script
  smakefile.ppc     =>  AMIGA smakefile for SAS C V6.58/7.00 PPC compiler
                        (Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)

scripts/libpng-config-head.in

@@ -11,7 +11,7 @@
 
 # Modeled after libxml-config.
 
-version=1.5.3beta03
+version=1.5.4beta01
 prefix=""
 libdir=""
 libs=""

scripts/libpng.pc.in

@@ -5,6 +5,6 @@ includedir=@includedir@/libpng15
 
 Name: libpng
 Description: Loads and saves PNG files
-Version: 1.5.3beta03
+Version: 1.5.4beta01
 Libs: -L${libdir} -lpng15
 Cflags: -I${includedir}

scripts/makefile.cegcc

@@ -23,7 +23,7 @@
 
 VERMAJ = 1
 VERMIN = 5
-VERMIC = 3
+VERMIC = 4
 VER = $(VERMAJ).$(VERMIN).$(VERMIC)
 NAME = libpng
 PACKAGE = $(NAME)-$(VER)

scripts/makefile.linux

@@ -10,7 +10,7 @@
 # Library name:
 LIBNAME = libpng15
 PNGMAJ = 15
-RELEASE = 3
+RELEASE = 4
 
 # Shared library names:
 LIBSO=$(LIBNAME).so

scripts/makefile.ne12bsd

@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include/libpng15
 
 LIB=	png15
 SHLIB_MAJOR=	0
-SHLIB_MINOR=	1.5.3beta03
+SHLIB_MINOR=	1.5.4beta01
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c

scripts/makefile.netbsd

@@ -17,7 +17,7 @@ INCSDIR=${LOCALBASE}/include
 
 LIB=	png
 SHLIB_MAJOR=	15
-SHLIB_MINOR=	1.5.3beta03
+SHLIB_MINOR=	1.5.4beta01
 SRCS=	png.c pngset.c pngget.c pngrutil.c pngtrans.c pngwutil.c \
 	pngread.c pngrio.c pngwio.c pngwrite.c pngrtran.c \
 	pngwtran.c pngmem.c pngerror.c pngpread.c

scripts/makefile.openbsd

@@ -11,7 +11,7 @@ LIBDIR=	${PREFIX}/lib
 MANDIR= ${PREFIX}/man/cat
 
 SHLIB_MAJOR=	15
-SHLIB_MINOR=	1.5.3beta03
+SHLIB_MINOR=	1.5.4beta01
 
 LIB=	png
 SRCS=	png.c pngerror.c pngget.c pngmem.c pngpread.c \

scripts/makefile.watcom

@@ -1,122 +0,0 @@
-# Makefile for libpng
-# Watcom C/C++ 10.0 and later, 32-bit protected mode, flat memory model
-
-# Copyright (C) 2000, Pawel Mrochen, based on makefile.msc which is
-# copyright 1995 Guy Eric Schalnat, Group 42, Inc.
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-# To use, do "wmake /f scripts\makefile.watcom"
-
-
-# ---------------------- Watcom C/C++ 10.0 and later -----------------------
-
-# Where the zlib library and include files are located
-ZLIBLIB=..\zlib
-ZLIBINC=..\zlib
-
-# Target OS
-OS=DOS
-#OS=NT
-
-# Target CPU
-CPU=6		# Pentium Pro
-#CPU=5		# Pentium
-
-# Calling convention
-CALLING=r	# registers
-#CALLING=s	# stack
-
-# Uncomment next to put error messages in a file
-#ERRFILE=>>pngerrs
-
-# --------------------------------------------------------------------------
-
-
-CC=wcc386
-CFLAGS=-$(CPU)$(CALLING) -fp$(CPU) -fpi87 -oneatx -mf -bt=$(OS) -i=$(ZLIBINC) -zq
-LD=wcl386
-LDFLAGS=-zq
-
-O=.obj
-
-OBJS1=png$(O) pngset$(O) pngget$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O)
-OBJS2=pngmem$(O) pngpread$(O) pngread$(O) pngerror$(O) pngwrite$(O)
-OBJS3=pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
-
-
-all: test
-
-# see scripts/pnglibconf.mak for more options
-# to support watcom calling conventions it is necessary to set PNG_API_RULE to 2
-# in pnglibconf.h - copy scripts/pnglibconf.h.prebuilt, delete the first line and change
-# the definition of PNG_API_RULE from 0 to 2.
-#
-# If you know how to do this with the Watcom build system please supply a patch
-# for this makefile to the PNG implementation list.
-pnglibconf.h: scripts/pnglibconf.h.prebuilt
-	@echo please copy scripts/pnglibconf.h.prebuilt and change PNG_API_RULE to 2
-
-png$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngset$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngget$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngpread$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngrtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngrutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngerror$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngmem$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngrio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwio$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngtest$(O): png.h pngconf.h pnglibconf.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngtrans$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwrite$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwtran$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-pngwutil$(O): png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-	$(CC) $(CFLAGS) $*.c $(ERRFILE)
-
-libpng.lib: $(OBJS1) $(OBJS2) $(OBJS3)
-	wlib -b -c -n -q libpng.lib $(OBJS1)
-	wlib -b -c -q libpng.lib $(OBJS2)
-	wlib -b -c -q libpng.lib $(OBJS3)
-
-pngtest.exe: pngtest.obj libpng.lib
-	$(LD) $(LDFLAGS) pngtest.obj libpng.lib $(ZLIBLIB)\zlib.lib
-
-test: pngtest.exe .symbolic
-	pngtest.exe
-
-
-# End of makefile for libpng

scripts/options.awk

@@ -48,7 +48,7 @@ BEGIN{
    deb=0                        # debug - set on command line
    everything=""                # do not override defaults
    logunsupported=0             # write unsupported options too
-   
+
    # Precreate arrays
    option[""] = ""    # list of all options: default enabled/disabled
    done[""] = 1       # marks option as having been output
@@ -301,7 +301,7 @@ pre != 0 && $1 == "chunk" && NF >= 2{
 #   macro is not defined.  The default value will be re-tokenised.
 #   (BTW: this is somewhat restrictive, it mainly exists for the
 #   support of non-standard configurations and numeric parameters,
-#   see the uses in scripts/options.dat 
+#   see the uses in scripts/options.dat
 
 $1 == "setting" && (NF == 2 || NF >= 3 && ($3 == "requires" || $3 == "default")){
    reqs = ""

scripts/pnglibconf.dfa

@@ -6,7 +6,7 @@
 #
 com pnglibconf.h - library build configuration
 com
-com libpng version 1.5.0 - January 6, 2011
+com libpng version 1.5.3 -  (PENDING RELEASE)
 com
 com Copyright (c) 1998-2011 Glenn Randers-Pehrson
 com
@@ -43,7 +43,7 @@ file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
 
 # The following setting, option and chunk values can all be changed
 # while building libpng:
-# 
+#
 # setting: change 'setting' lines to fine tune library performance,
 #   changes to the settings don't affect the libpng API functionally
 #
@@ -62,7 +62,7 @@ file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
 # don't want in that file in that file.  You can also turn on options
 # using PNG_<option>_SUPPORTED.  When you have finished rerun
 # configure and rebuild pnglibconf.h file with -DPNG_USER_CONFIG:
-# 
+#
 #  make clean
 #  CPPFLAGS='-DPNG_USER_CONFIG' ./configure
 #  make pnglibconf.h
@@ -73,7 +73,7 @@ file pnglibconf.h scripts/pnglibconf.dfa PNGLCONF_H
 #
 # 2) Add definitions of the settings you want to change to
 # CPPFLAGS; for example:
-# 
+#
 #   -DPNG_DEFAULT_READ_MACROS=0
 #
 # (This would change the default to *not* use read macros.)  Be
@@ -193,11 +193,11 @@ option FLOATING_ARITHMETIC
 option FLOATING_POINT enables ok_math
 option FIXED_POINT enables ok_math
 
-# Added at libpng version 1.4.0 
+# Added at libpng version 1.4.0
 
 option ERROR_TEXT
 
-# The following is always on (defined empty) 
+# The following is always on (defined empty)
 
 setting CALLOC_SUPPORTED default
 
@@ -214,9 +214,9 @@ option STDIO
 option CONSOLE_IO requires STDIO
 
 # Note: prior to 1.5.0 this option could not be disabled if STDIO
-# was enabled.
+# was enabled.  Prior to 1.5.3 this option required STDIO
 
-option TIME_RFC1123 requires STDIO
+option TIME_RFC1123
 
 # PNG_SETJMP_NOT_SUPPORTED is an old equivalent for NO_SETJMP
 
@@ -311,11 +311,13 @@ option READ_BGR requires READ_TRANSFORMS
 option READ_SWAP requires READ_TRANSFORMS READ_16BIT
 option READ_PACKSWAP requires READ_TRANSFORMS
 option READ_INVERT requires READ_TRANSFORMS
-option READ_BACKGROUND requires READ_TRANSFORMS
+option READ_BACKGROUND requires READ_TRANSFORMS enables READ_STRIP_ALPHA
 option READ_16_TO_8 requires READ_TRANSFORMS
 option READ_FILLER requires READ_TRANSFORMS
 option READ_GAMMA requires READ_TRANSFORMS enables READ_gAMA
 option READ_GRAY_TO_RGB requires READ_TRANSFORMS
+
+option READ_ALPHA_MODE requires READ_TRANSFORMS enables READ_GAMMA
 option READ_SWAP_ALPHA requires READ_TRANSFORMS
 option READ_INVERT_ALPHA requires READ_TRANSFORMS
 option READ_STRIP_ALPHA requires READ_TRANSFORMS
@@ -340,12 +342,17 @@ option READ_COMPOSITE_NODIV requires READ
 option INCH_CONVERSIONS
 = INCH_CONVERSIONS INCH_CONVERSIONS
 
+# API to build a grayscale palette
+
+option BUILD_GRAYSCALE_PALETTE
+
+option READ_16_TO_8_ACCURATE_SCALE requires READ
+option LEGACY_READ_16_TO_8_ACCURATE_SCALE disabled
+
 # IN DEVELOPMENT
-# These are currently experimental features, define them if you want
+# These are currently experimental features; define them if you want
 
-# Very little testing, not enabled by default.
-
-option READ_16_TO_8_ACCURATE_SCALE requires READ disabled
+# NOTHING HERE
 
 # WRITE options
 
@@ -546,6 +553,10 @@ option SAVE_INT_32 requires WRITE
 
 # png_save_int_32 is required by the ancillary chunks oFFs and pCAL
 
+# added at libpng-1.5.3
+option WRITE_OPTIMIZE_CMF requires WRITE
+
+option READ_COMPRESSED_TEXT disabled
 option READ_iCCP enables READ_COMPRESSED_TEXT
 option READ_iTXt enables READ_COMPRESSED_TEXT
 option READ_zTXt enables READ_COMPRESSED_TEXT
@@ -554,11 +565,13 @@ option READ_COMPRESSED_TEXT enables READ_TEXT
 option WRITE_oFFs enables SAVE_INT_32
 option WRITE_pCAL enables SAVE_INT_32
 
+option WRITE_COMPRESSED_TEXT disabled
 option WRITE_iCCP enables WRITE_COMPRESSED_TEXT
 option WRITE_iTXt enables WRITE_COMPRESSED_TEXT
 option WRITE_zTXt enables WRITE_COMPRESSED_TEXT
 option WRITE_COMPRESSED_TEXT enables WRITE_TEXT
 
+
 # Turn this off to disable png_read_png() and png_write_png() and
 # leave the row_pointers member out of the info structure.
 

scripts/pnglibconf.h.prebuilt

@@ -17,7 +17,7 @@
 /* pnglibconf.dfa with respect to the dependencies between the following */
 /* symbols.  It is much better to generate a new file using */
 /* scripts/libpngconf.mak */
-  
+
 #ifndef PNGLCONF_H
 #define PNGLCONF_H
 /* settings */
@@ -43,6 +43,7 @@
 #define PNG_ALIGN_MEMORY_SUPPORTED
 #define PNG_BENIGN_ERRORS_SUPPORTED
 #define PNG_bKGD_SUPPORTED
+#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
 #define PNG_CHECK_cHRM_SUPPORTED
 #define PNG_cHRM_SUPPORTED
 #define PNG_CONSOLE_IO_SUPPORTED
@@ -60,6 +61,7 @@
 #define PNG_INFO_IMAGE_SUPPORTED
 #define PNG_IO_STATE_SUPPORTED
 #define PNG_iTXt_SUPPORTED
+/*#undef PNG_LEGACY_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED*/
 #define PNG_MNG_FEATURES_SUPPORTED
 #define PNG_oFFs_SUPPORTED
 #define PNG_pCAL_SUPPORTED
@@ -67,7 +69,9 @@
 #define PNG_POINTER_INDEXING_SUPPORTED
 #define PNG_PROGRESSIVE_READ_SUPPORTED
 #define PNG_READ_16BIT_SUPPORTED
+#define PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
 #define PNG_READ_16_TO_8_SUPPORTED
+#define PNG_READ_ALPHA_MODE_SUPPORTED
 #define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
 #define PNG_READ_BACKGROUND_SUPPORTED
 #define PNG_READ_BGR_SUPPORTED
@@ -152,9 +156,10 @@
 #define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
 #define PNG_WRITE_INVERT_ALPHA_SUPPORTED
 #define PNG_WRITE_INVERT_SUPPORTED
-#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
+#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 #define PNG_WRITE_iTXt_SUPPORTED
 #define PNG_WRITE_oFFs_SUPPORTED
+#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
 #define PNG_WRITE_PACK_SUPPORTED
 #define PNG_WRITE_PACKSWAP_SUPPORTED
 #define PNG_WRITE_pCAL_SUPPORTED
@@ -179,6 +184,5 @@
 #define PNG_zTXt_SUPPORTED
 #define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
 /*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
-/*#undef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED*/
 /* end of options */
 #endif /* PNGLCONF_H */

scripts/pnglibconf.mak

@@ -1,6 +1,6 @@
 #!/usr/bin/make -f
 # pnglibconf.mak - standard make lines for pnglibconf.h
-# 
+#
 # These lines are copied from Makefile.am, they illustrate
 # how to automate the build of pnglibconf.h from scripts/pnglibconf.dfa
 # given 'awk' and 'sed'

scripts/symbols.def

@@ -5,7 +5,7 @@
 LIBRARY
 
 EXPORTS
-;Version 1.5.3beta03
+;Version 1.5.4beta01
  png_access_version_number @1
  png_set_sig_bytes @2
  png_sig_cmp @3
@@ -232,3 +232,5 @@ EXPORTS
  png_set_text_compression_strategy @224
  png_set_text_compression_window_bits @225
  png_set_text_compression_method @226
+ png_set_alpha_mode @227
+ png_set_alpha_mode_fixed @228

test-pngvalid-full.sh

@@ -7,9 +7,9 @@ echo >> pngtest-log.txt
 echo "============ pngvalid-full.sh ==============" >> pngtest-log.txt
 
 echo "Running test-pngvalid-full.sh"
-for gamma in threshold transform sbit 16-to-8
+for gamma in threshold transform sbit 16-to-8 background alpha-mode "transform --expand16" "background --expand16" "alpha-mode --expand16"
 do
-   if ./pngvalid "--gamma-$gamma" >> pngtest-log.txt 2>&1
+   if ./pngvalid --gamma-$gamma >> pngtest-log.txt 2>&1
    then
       echo "  PASS:" pngvalid "--gamma-$gamma"
    else